This conference presentation was prepared for SPIE Photonics West, 2024.

Optical lattice clocks have demonstrated unprecedented performance below the 10^-18 fractional level, advancing towards new standards of timekeeping and sensitive probes in fundamental physics. To further advance optical lattice clocks performance, it is crucial to attain lower temperatures which facilitates the use of shallow lattices with reduced light shifts, while retaining large atom numbers to reduce the quantum projection noise. Here, we present Sisyphus cooling using the long-lived 3P0 clock state in alkaline-earth-like ytterbium. Upon excitation on the ultranarrow clock transition, Sisyphus cooling is observed within a spatially periodic potential induced by a 1388-nm optical standing wave that is nearly resonant with the 3P0 → 3D1 transition. Our cooling demonstrates versatility, working both in free space and in a magic-wavelength lattice. It offers the flexibility of being employed in either pulsed or continuous modes, making it suitable to a range of quantum metrology applications.

We report on progress in the characterization of systematic shifts in chip-scale atomic beam clocks, which offer the potential for improved long-term stability relative to existing chip-scale atomic clocks. Previous work has demonstrated the key features of chip-scale atomic beam devices including the use of a microfabricated Si/glass atomic beam cell, passively maintained vacuum environment, and an integrated Rb atomic beam source. A beam clock has been realized using Ramsey coherent population trapping interrogation with a demonstrated short-term fractional frequency stability of ≈ 1.2 × 10^(-9)at 1 s of integration. In this talk, we discuss the path toward long-term stabilty in chip-scale atomic beam clocks and leading clock systematics. Chip-scale atomic beams are a new platform for quantum sensing which offer the potential for long-term stability in compact, low-power applications.

Ultracold atom techniques have transformed our ability to perform precise spectroscopy and apply it to time and frequency metrology. Some of the highest-performing atomic clocks are based on laser-cooled atoms in optical lattice traps. These clocks can be applied to fundamental questions, for example to improve our understanding of gravity and general relativity. I will discuss optically trapped molecules as a basis for clocks. Molecules have more internal quantum states and therefore are relatively challenging to control. On the other hand, their vibrational modes offer a large number of prospective clock transitions, and can help us probe alternative aspects of new physical interactions. I will also describe the current precision limit of molecular metrology and possible paths forward.

We present a range of technology solutions aimed at miniaturising cold atom microwave atomic clocks. This includes the integration of a grating magneto-optic trap with a compact loop-gap microwave cavity, the use of an optical Raman excitation scheme for increased detection sensitivity, the development of cm-scale bespoke vacuum systems, and progress towards MEMS cold-atom and frequency reference vapour cells. The prospect for using the latter in miniaturised optical atomic clocks will be highlighted.

Vertical-external-cavity surface-emitting lasers (VECSELs) have emerged as an attractive single-frequency laser platform for quantum computing and -sensing applications including optical clocks. VECSELs exhibit a unique combination of features including high-power single-frequency operation, excellent beam, and the ability to cover a broad wavelength range from the ultraviolet to visible and to infrared. Here a compact commercial VECSEL platform with sub-Hz linewidth for optical lattice clocks is presented including recent data for Sr and Yb systems.

In this talk, I will present our recent results on Kerr-induced synchronization (KIS) of octave-spanning microcombs and discuss how they can impact clockworks for optical atomic clocks. With KIS, we achieve all-optical locking of a microcomb to a reference laser (which can be linked to an atomic frequency reference), bypassing the need for active beat note detection and servo control, and naturally leading to optical frequency division of the reference laser onto the Kerr comb repetition rate. I will also discuss how KIS dramatically improves our ability to self-reference the Kerr comb and detect its carrier-envelope offset frequency. Finally, I’ll outline our efforts to further advance KIS of microcombs in support of a Rb 2-photon optical clock.

We present NPL’s recent contributions to timekeeping applications of optical clocks. The first of these in-volves optical clocks at NPL and SYRTE being simultaneously used to steer experimental time scales, in a similar manner to Cs fountains steering the national time scales. The resulting optically-steered time scales at NPL and SYRTE (denoted UTCx(NPL) and UTCx(OP) respectively) will be presented along with compari-sons against both Coordinated Universal Time (UTC) and each other via satellite techniques. We will then present how optical clocks can be used in the evaluation and steering of International Atomic Time (TAI) and, subsequently, UTC – a feat which has recently been achieved by NPL’s Sr lattice optical clock. We will discuss the process by which this was achieved, and we will show the recent frequency data and analysis that has been used to perform recent calibrations of TAI.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

We will provide an overview of the advancement in reducing the size of a high-performance portable Rubidium clock. Afterwards, we will discuss strategies on how the photonic integrated circuit technology can be used to further reduce the size, weight and power of the Rubidium clock for future PNT applications.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

We investigate the feasibility of optical-to-microwave photon conversion, intended for quantum radar (QR), using a six-wave mixing scheme in Rb-87 Rydberg state atomic vapor. Coherence between entangled microwave photons affords QR a significant gain in remote sensing performance relative to conventional radar at the same power level. The challenge of QR comes from developing compact sources and detectors for entangled microwave photons. Existing demonstrations of entangled microwave photon generation require bulky dilution refrigerators. Our approach explores entangled, 84GHz microwave photon generation through Rydberg atom-based quantum frequency conversion of optical entangled photons. The high frequency (84GHz) relaxes the cooling requirement for suppressing thermal background and lies in the W-band (75GHz – 110GHz) atmospheric transparency window with 0.1dB/km loss. Microwave photon detection can be performed by reversing the six-wave mixing process for microwave-to-optical conversion.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

The negatively charged silicon vacancy center (SiV-) in diamond is a promising candidate for single-spin quantum sensing at sub-kelvin temperatures, which requires shallow and optically coherent emitters. We present a robust, scalable approach for creating individual, ∼50nm deep SiV- with lifetime-limited optical linewidths in diamond-nanopillars through an easy-to-realize charge-stabilization scheme, based on 445nm illumination, enabling continuous PLE spectroscopy, without further charge stabilization or repumping. Our results constitute a key step towards the use of near-surface, optically coherent SiV- for sensing under extreme conditions, and offer a powerful approach for stabilizing the charge-environment of diamond color centers for quantum technology applications.

Error correction in measurement-based quantum computing schemes will require the construction of cluster states in at least 3 dimensions. Here, we generate 1-, 2-, 3-, and 4-dimensional optical frequency-mode cluster states by sending broadband 2-mode vacuum-squeezed light through an electro-optical modulator (EOM) driven with multiple frequencies. We create the squeezed light using 4-wave mixing in Rb atomic vapor and mix the sideband frequencies (qumodes) using an EOM, producing a pattern of entanglement correlations that constitute continuous-variable graph states containing up to several hundred qumodes. We verify the entanglement structure by using homodyne measurements to construct the covariance matrices and evaluate the nullifiers. This technique enables the scaling of optical cluster states to multiple dimensions without increasing loss.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

Recent years have seen a strong interest in the possibility to enhance classical and quantum sensing in suitably engineered non-Hermitian multimode systems, displaying e.g. parity-time symmetry or topological phases. The bosonic Kitaev-Majorana chain is a proposed non-Hermitian topological model that is predicted to feature enhanced responsivity to small perturbations, linked to unidirectional amplification. We report an experimental realization of the bosonic Kitaev chain in a nano-optomechanical network, in which two-mode squeezing and beamsplitter interactions between nanomechanical modes are generated through temporally modulated radiation pressure control fields. We demonstrate that this system displays a dramatic sensitivity to boundary conditions, and a unique exponential scaling of the responsivity to a small perturbation with the number of resonators.

This conference presentation was prepared for SPIE Photonics West, 2024.

Phase estimation plays a central role in communications, sensing, and information processing. Here, we propose a novel adaptive Gaussian measurement strategy for optical phase estimation with squeezed vacuum states with precision close to the quantum limit. By constructing a comprehensive set of locally optimal positive operator-valued measures (POVMs) through rotations and homodyne measurements, our approach optimizes the adaptive measurement process using the complete homodyne measurement records. This adaptive phase estimation strategy outperforms previous approaches for phase estimation and approaches the quantum limit within the phase interval of [0,π/2). We further generalize this adaptive strategy to incorporate heterodyne measurements, enabling near quantum-limited precision for phase estimation across the entire range of phases from [0,π). Remarkably, our proposed strategy approaches an asymptotic optimal performance in this phase interval, which corresponds the maximum range of phases that can be unambiguously encoded in squeezed vacuum states.

This conference presentation was prepared for SPIE Photonics West, 2024.

With the advancement in low-threshold detector technology over the last decade, the high energy physics community has increasingly been able to probe for new physics at low energies. Specifically, searching for low mass dark matter, and single counting of THz photons. Orders of magnitude in sensitivity and new physics reach can be made by exploring quantum materials and superconducting qubits as particle detectors.

Over the last decade, several low-energy physics searches, including those for particle dark matter, have driven interest in developing increasingly sensitive particle detectors. Superconducting (SC) quantum sensors based on broken Cooper Pairs provide a possible channel for sensing O(meV) energy depositions, and may be a significant step in developing such low-threshold detectors. The Quantum Science Center group at Fermilab is exploring the use of superconducting qubits for particle detection in the LOUD surface dilution fridge facility and the QUIET underground facility. This talk will discuss recent efforts to understand qubit response to energy depositions through a combination of measurements in LOUD and low-energy G4CMP simulations of phonons and Bogoliubov quasiparticles within our superconducting qubit chips. We also show progress on modeling phonon transport in a variety of new materials, as well as ongoing improvements of the superconductor response to energy depositions. We close with a discussion of prospects for measurements within the QUIET facility to understand the impact of reducing ambient backgrounds on qubit performance in the context of dark matter searches.

This conference presentation was prepared for SPIE Photonics West, 2024.

The isolation afforded by levitated optomechanics, combined with the ability to detect ultraweak forces in three directions, makes them particularly interesting for directional dark searches. This directionality allows 3D reconstruction of an interaction with increased background rejection, even with only a few detection events. We will discuss a levitated sensor that is being developed to place new bounds on composite dark matter by detecting their collisions with trapped nanoparticles. We will describe the 3-D electrical cold damping scheme used in this experiment as well as the electrode configuration that allow us to provide a well-defined directional impulse calibration. We will also present a preliminary analysis of the first experimental data run that is currently underway.

The extraordinary advances in quantum control of matter and light have been transformative for atomic and molecular precision measurements enabling probes of the most basic laws of Nature to gain a fundamental understanding of the physical Universe. The development of high-precision optical atomic clocks enables searches for the variation of fundamental constants, dark matter, violations of Lorentz invariance, and tests of gravity. Deployment of high-precision clocks in space will open the door to new applications, including precision tests of gravity and relativity, searches for a dark-matter halo bound to the Sun, and gravitational wave detection in wavelength ranges inaccessible on Earth, and others. I will give a broad overview of atomic clock applications on Earth and in space, focusing on searches for physics beyond the standard model of elementary particles. Several examples will be highlighted, including dark matter searches with atomic and nuclear clocks and new ideas for searches of physics beyond the standard model with quantum sensors in space. New ideas for detection of transient signals will be presented.

This conference presentation was prepared for SPIE Photonics West, 2024.

We present a novel type of direct detector for axions and axion-like particles. Our approach utilizes a high-finesse optical cavity, where the polarization axis of a linearly polarized laser beam undergoes rotation induced by the axion field of the galactic halo. In our first observing run, the detector reached a peak sensitivity of 1.44*10^(-10) GeV^(-1) (at a 95 % confidence level) to the axion-photon coupling strength in the mass range of 1.97-2.01 neV, establishing it as one of the most sensitive axion detectors currently available. We provide the latest update on the sensitivity figures and discuss our pathway towards surpassing the current sensitivity limits in the mass range from 10^(-8) eV down to 10^(-16) eV. This involves implementing a squeezed light source and adjusting the measurement band via the resonance separation in our cavity.

New physics and novel applications in various fields ranging from biology, and spectroscopy, to manipulation of quantum systems are driven by the availability of coherent light sources including ultrafast coherent frequency combs in the visible and mid-infrared frequency regimes. Nonlinear optical systems, that are parametrically driven by technologically mature near-infrared radiation, are leveraged in this regard to access these challenging wavelengths where conventional lasers maybe unavailable. It is of paramount importance to miniaturize these systems and replace the traditional bulky setups thereby paving the way for a plethora of disruptive applications.

In this talk, I will discuss our results in realizing these parametrically driven oscillators in an integrated lithium-niobate nanophotonics platform and the demonstration of the first-of-its-kind mid-infrared frequency comb source that is widely tunable over an octave accompanied by visible frequency comb generation. I will present how we can exploit the nonlinear dynamics to generate ultra-short pulses from these parametrically driven nonlinear resonators. I will conclude my talk with a glimpse of exciting developments with regard to lithium niobate nanophotonics in the context of ultra-fast mode-locked lasers.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

Photonically integrated resonators are promising as a platform for enabling ultranarrow linewidth lasers in a compact form factor. Owing to their small size, these integrated resonators suffer from thermal noise that limits the frequency stability of the optical mode to ∼100 kHz. We show here an integrated stimulated Brillouin scattering (SBS) laser based on a large mode volume annulus resonator that realizes a thermorefractive-limited linewidth of 270 Hz. Despite these efforts in thermal noise reduction, yet narrower linewidths are required before integrated lasers can be truly useful for applications such as optical atomic clocks, quantum computing, gravitational wave detection, and precision spectroscopy. We demonstrate here some techniques to further suppress the linewidth of chip-integrated lasers, reaching levels below 30 Hz.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

Stimulated Brillouin scattering (SBS) is often considered to be problematic, since it limits optical power in telecom and RF photonics applications. However, the highly efficient and narrowband SBS process also provides unique functionality that can be used for a variety of applications. In this talk, I will present recent work exploiting SBS for applications in distributed fiber sensing and high-resolution spectroscopy. First, I will present work showing how the complex Stokes and anti-Stokes interactions can be used to perform distributed temperature and strain measurements with immunity to cross-talk. To achieve higher sensitivity, we introduced a technique that operates by exciting up to 1000 Brillouin lasing modes simultaneously in a fiber ring cavity. We then showed that modifications to these schemes can enable high-resolution spectroscopy with unique combinations of bandwidth, resolution, and measurement rate.

We will present the last developments on MIGA, a 150 m horizontal gravity-gradiometer being built underground as a demonstrator for gravitational wave detection using atomic sensors. We demonstrated the multi-photon Bragg diffraction in a prototype optical resonator 80 cm long, where we made use of the cavity modal structure to boost the atom optics efficiency. We will report on the work progress of the large baseline infrastructure.

Atom interferometry is a quantum sensor technology that uses ultra-cold atoms placed in entangled quantum states to detect minute changes in local fields arising from gravitational waves and ultra-light dark matter. Their extreme sensitivity to accelerations has been demonstrated for measurements of Newton’s gravitation constant, tests of the Equivalence Principle, and measurement of local gravity gradients. The search for ultra-light dark matter and measurements of gravitational waves requires interferometer baselines greater than approximately 100 m. In understanding the fundamental systematics and backgrounds of these detectors, we have discovered that atmospheric and seismic effects, even though physically decoupled from the atoms which are in vacuum and free-fall, are still detectable by the quantum phase of the atoms. From a different perspective these “noise” sources are also interesting signals that we may be able to understand better with these sensor platforms leading to cross-disciplinary studies in Earth sciences.

In 2015 Exail launched on the marketplace the first gravimeter based on quantum manipulation of laser-cooled atoms. Phase-locked Raman beams open an 87Rb atom interferometer sensitive to the vertical acceleration. Thorough technology developments like frequency-doubled telecom lasers and micro-optic benches had brought the autonomy and robustness necessary for field-deployment. We will present a 3-years measurement campaign on Mt Etna, Sicily, an active volcano. We will furthermore demonstrate the reproducible performances of 10^-9 g resolution after < 2h measurement time (< 40 min on a quiet site) confirmed on all 15 built units. On-going research evaluates systematic effects to 10^-9 g or better. Future projects will bring our quantum gravimeters to moving platforms.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

Extended free fall enables experiments with quantum gases unbiased by gravity. Apart from a 10m-fountain, we have access to various platforms comprising the Bremen drop- and gravi-tower, the Einstein Elevator, sounding rockets as well as NASA‘s cold atom laboratory (CAL) in orbit, all offering experiments with different durations and repetition rates. Atom chips turned out to successfully create Rubidium Bose-Einstein condensates on these platforms. Recently we have lowered the expansion energies of Bose-Einstein condensates to an unprecedented level corresponding to 38pK which makes them an excellent resource for interferometry. We exploit the latter to study delta-kick collimation as well to extend interferometry times in free fall. Atom chips also allow to investigate quantum mixtures in absence of bouyancy. For this purpose, we have been creating potassium 41 BECs by sympathetic cooling with rubidium. These experiments were continued to space by sounding rocket missions and the CAL. In future, the recently inaugurated Einstein elevator as well as gravitower will be important platforms to increase the experimental cycles to study quantum gas mixtures and high-precision interferometry as well as to test fundamental physics such as Einstein’s principle of equivalence and the nature of dark energy on ground in free fall.

Very Long Baseline Atom Interferometry (VLBAI) enables ground-based inertial sensing with largest scale factors. Combined with control over noise sources and systematic effects, VLBAI holds the potential for unprecedented tests of fundamental physics in the domains of gravity, quantum mechanics, and at their interface, as well as for new frontiers in Earth observation, e.g., by operating the system as a higher order absolute gravity reference station. In this contribution we will discuss recent developments and future prospects of the Hannover VLBAI facility.

This conference presentation was prepared for SPIE Photonics West, 2024.

There are rapidly growing demands for more compact and lower-noise optical sources that can operate in non-laboratory environment, including radars and field-deployed spectroscopy. Here we employed a self-homodyne Michelson interferometer, utilizing an optical fiber delay-line as a reference, to suppress the frequency noise of a continuous-wave laser and optical frequency comb. We achieved the frequency instability of 10^(-15)- and 10^(-14)-level for CW laser and optical frequency comb, at 9-ms and 0.1-s averaging time respectively. Additionally, we improved the vibration sensitivity by optimizing the design of an aluminum cylinder with a groove, resulting in a 10^(-10) [1/g] vibration sensitivity.

We demonstrate that a quantum receiver can monitor the conditions of a communications channel simultaneously with data transmission, with no additional measurements required. The sensing scheme uses the confidence vector estimated by the state identification algorithm to monitor changes in power and phase noise and is demonstrated experimentally. To measure confidence, the output of the quantum receiver is processed using the Bayesian formula for each individual measurement. By optimizing the statistical analysis of confidence vector data we achieve 0.5% sensitivity to power fluctuations with no interruption of data transmission.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

Room-temperature MASERs (Microwave Amplification by Stimulated Emission of Radiation) are coherent sources that exploit stimulated emission to amplify electromagnetic waves at microwave frequencies. Here we report the first demonstration of an LED-pumped maser based on photo-excited triplet states of pentacene in p-terphenyl. The LED light is brightness enhanced and guided using a Cerium-doped Yttrium Aluminium Garnet luminescent crystal that uses light recycling to reach record luminance and power levels. We observe stable maser emission at 1.45 GHz using LED pumping at a much lower pump threshold power. This new maser is cost-effective, safe, and environmentally friendly, and hence ensures a wide variety of potential uses, including more sensitive magnetic resonance body scanners, quantum optical coherence tomography, advanced quantum computer components, portable atomic clocks, and better radio astronomy devices for deep space exploration.

This talk will present the world first results related to a compact, high power, room temperature continuous wave terahertz semiconductor laser diodes emitting in a wide frequency range (1-5 THz) based on intracavity difference frequency generation.

Numerous precision metrology systems for detecting quanta of any kind are based on silicon detectors. Recently, low-gain avalanche detectors (LGAD) with fast response and reduced noise level have been proposed. Beneficial applications of LGADs developed by CiS [1] in quantum detection e.g. in electron detection systems will be shown. Nevertheless, under strong irradiation the gain layer of theses LGADs disappears possibly due to formation of ASi-Sii-defects.[2] These defects are point defects in silicon with several metastable configurations in 3 charge states. These are controllable e.g. by light and temperature. Some of them are luminescing, making this defect an interesting candidate in quantum applications, as well. Targeted manipulation by light and temperature of these PL lines in the indium (InSi-Sii) and thallium (TlSi-Sii) case will be shown. Progress in ASi-Sii-defect modelling will be presented and implications for LGAD development and applications in quantum science of these intereseting defcts in silicon are pushed forward. [1] K. Lauer et al., Phys. Status Solidi A 219(17), 2200177 (2022). [2] K. Lauer et al., Phys. Status Solidi A 219(19), 2200099 (2022).

A beam’s spatial distribution can be structured in terms of its amplitude and phase, and the transverse and longitudinal distribution can be tailored by an appropriate transmission of modes. This presentation will highlight longitudinally-structured light fields. (a) Sensing: To mitigate atmospheric turbulence effects, knowledge of turbulence strength at various distances could be valuable. One approach for probing utilizes multiple sequentially transmitted longitudinally structured beams, each on the same wavelength. Each beam is composed of Bessel-Gaussian modes with different longitudinal wavenumbers such that a distance-varying beam width is produced, which results in a distance- and turbulence-dependent power coupling to other spatial modes. (b) Dynamic Behavior: Space-time wave packets (STWPs) can have spatiotemporal evolution that is arbitrarily engineered to occur at various distances along the longitudinal propagation path. This can be achieved by introducing a 2-D spectrum comprising both temporal and longitudinal wavenumbers associated with specific transverse Bessel-Gaussian fields, resulting in packets evolving in time and distance.

Dark energy, a mysterious form of energy that pervades the entire universe, is believed to be responsible for the accelerated expansion of the universe. Various theoretical attempts have been made to explain its elusive nature. One appealing model is the so-called symmetron dark energy model, which predicts a fifth force that interacts with matter. However, the screening of the fifth force in high-density environments poses a challenge for laboratory experiments. Although several experiments have constrained certain aspects of the model's parameter space, a vast and unexplored parameter space still remains. Here, we have constructed a novel experimental platform based on a magnetically levitated force sensor to search for the symmetron fifth force at the sub-millimeter scale, with a specially designed structure to minimize screening effects. Through this approach, we have improved the limits of the model by over six orders of magnitude within the three-dimensional parameter space. Our findings demonstrate the tremendous potential of our system in probing forces beyond the standard model.

Optomechanical devices are being actively harnessed as sensors for ultraweak forces, with a growing range of applications including inertial sensing or dark matter sensors. Dark matter searches aim to use directional detection to discriminate from interfering backgrounds. We present a calibration-free approach to measurements of directional stochastic forces by using the cross-correlation power spectra. We show that these provide a distinctive signature of the presence of a directional broad-spectrum force, as well as its orientation quadrant. Accurate measurement of the angle offers something akin to a force compass in the x-y plane and a promising tool for dark matter searches.

A levitated nanomechanical oscillator under ultra-high vacuum (UHV) is highly isolated from its environment. It has been predicted that this isolation leads to very low mechanical dissipation rates. However, a gap persists between predictions and experimental data. Here, we levitate a silica nanoparticle in a linear Paul trap at room temperature, at pressures as low as 7e-11 mbar. We measure a dissipation rate of 2*pi*80(20) nHz, corresponding to a quality factor exceeding 1e10, more than two orders of magnitude higher than previously shown. A study of the pressure dependence of the particle's damping and heating rates provides insight into the relative dissipation mechanisms.

The optical centrifuge is an established tool in molecular physics for inducing controlled rotation of molecules through the transfer of angular momentum from an optical field. Here the polarization vector is rapidly rotated up to high angular velocities, which subsequently rotates molecules up to high angular frequencies. This technique has been instrumental in studying molecular structure and collision processes. Recently, there has been significant interest in controlling the rotational motion of nanorotors to study non-classical states in these macroscopic systems. We describe the creation of an optical centrifuge for nanorotors formed by anisotropic nanoparticles levitated within an optical tweezer. We present a classical description of this process and discuss optimal schemes for the acceleration of the linear polarization vector to well-defined rotational frequencies. We report on the experimental realization of the centrifuge enabled by a fast in-line polarization controller. This approach is also compared to rapid switching between linear and elliptically polarized fields. Finally, we describe future experiments to probe the quantum nature of rotation in these systems.

The repeated measurements of neutrino oscillations over the last few decades confirm that neutrinos have non-zero masses which are not accounted for in the Standard Model. The observed small neturino masses can be explained by introducing a massive right-handed "sterile neutrino" that does not interact through the weak force. One class of experiments searching for sterile neutrinos utilise radioactive decays to generate neutrinos and search for deviations in the recoil energy spectra of the daughter nucleus that would suggest mixing between Standard Model neutrinos and a sterile neutrino. We present a new experiment that is currently being realised that utilises levitated nanoparticles doped with a radioactive isotope to measure the momentum of the recoiling daughter nucleus and reconstruct the momentum of the emitted neutrino. Measuring momentum rather than energy significantly reduces the impact of low or zero mass backgrounds and secondary emissions. This search will improve sensitivity to sterile neutrinos in the mass range 100 keV - 2 MeV compared to previous experiments.

We present the first experimental prototype of a stable phase-insensitive optomechanical quantum filter designed to enhance the shot-noise-limited sensitivity of interferometers, such as gravitational-wave detectors and axion detectors, without use of squeezed light. Our prototype features a high-Q silicon nitride membrane that is dispersively coupled to a system of two coupled optical cavities with a total length of approximately 6 meters, making it the first meter-scale system optomechanically coupled to a nano-object and operating in the resolved sideband regime. We report on the latest results and discuss other potential applications of our prototype, including optomechanical cooling below the ground-state level, quantum non-demolition measurements of the quantum states of the membrane, and strong coherent coupling of two nano-objects separated by a distance of several meters.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

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Atomic and Molecular Physics is a discipline rich with discoveries in quantum science. Over the last century, these discoveries have repeatedly transformed scientific and technological landscapes and continue to do so, ultimately changing our way of life. This talk introduces the Air Force Office of Scientific Research (AFOSR), a part of the Air Force Research Laboratory that funds work satisfying the basic research needs of the Air Force and Space Force, and offers an overview of the Atomic and Molecular Physics portfolio at AFOSR. Distribution A. Approved for public release: distribution unlimited (AFRL-2023-6227).

Sensors based on quantum mechanical properties of light and matter offer unique capabilities and performance sometimes difficult to achieve using classical approaches. NASA Engineering and Safety Center has convened an independent external panel, comprised of Quantum Sensing Experts from the Government, DoD, academia, and Federally funded Research and Development Centers to conduct an independent technical assessment of the agency's capabilities in Quantum Sensing to understand NASA's internal needs and competencies related to Quantum Sensing and compare agency capabilities with those available externally including industry, academia, and other government agencies. This assesses focused on suitability of quantum sensing for current and future NASA needs. Measurement and sensing needs across NASA were reviewed as a driver for the possible incorporation of existing quantum sensors into the NASA portfolio and the development of next-generation quantum sensors. This presentation will describe a set of findings and recommendations to guide future investment and activity at NASA in this important and growing technology area.

Traditional spontaneous parametric down-conversion (SPDC) generally has a broad spectral band, while quantum optical coherence tomography (QOCT) aims to achieve an ultra-broadband joint spectrum to ensure good axial resolution. Ultra-broadband supercontinuum (SC) sources enable axial resolutions of approximately 1 µm in OCT. This study investigates the impact of ultra-broadband SPDC using an SC source to generate entangled photon pairs within the 700-1000 nm range. By examining the tuning capabilities and dimensional design of the Beta Barium Borate (BBO) crystal, we explore the combination of the OCT SC source and SPDC for QOCT. The findings contribute to future developments in QOCT.

We introduce quantum microscopy by coincidence (QMC) featuring balanced pathlengths, which facilitates super-resolution imaging at the Heisenberg limit, drastically boosting speed and contrast-to-noise ratio (CNR) compared to existing wide-field quantum imaging methods. QMC uses correlated photons traversing symmetric paths, behaving like a photon with half the wavelength for twice the resolution. It withstands 155 times stronger stray light than classical signals, promising non-destructive bioimaging. Our approach propels quantum imaging to microscopic scale by imaging cancer cells. Experimental and theoretical results endorse this balanced pathlength configuration as a path to quantum-enhanced coincidence imaging at the Heisenberg limit.

We build a test setup for metrological characterization of the qCMOS photon number-resolving camera. We evaluate the quality of the photon number distributions measured with the camera for coherent and pseudo-thermal sources and perform quantum tomography of the camera. Further, we make measurements of multiple spatially overlapping pseudo-thermal states to perform full statistical mode reconstruction and calculate the spatial distribution of the high-order correlation functions $g^{(n)}(0)$. We use the obtained results to demonstrate spatio-angular super-resolution with a photon number-resolving camera. The methods reported here can be used as a toolkit for quantum super-resolving microscopy with photon number-resolving cameras.

We investigate two different approaches for imprinting orbital angular momentum (OAM) on different spectral components of a broadband ultraviolet beam with wavelength 350-500 nm for application in quantum optical coherence tomography. Two different approaches using a spiral phase plate (SPP) are studied to achieve this goal. The first approach involves using only a SPP, calibrated for a particular wavelength, for broadband application. However, this approach leads to the presence of unmodulated components in the output beam. In the second approach, combination of SPP and grating is used to remove the unmodulated part and to filter out the imprinted OAM beam. ACKNOWLEDGEMENTS This work is supported by Villum Fonden (Villum Investigator project Table-Top Synchrotrons, No. 00037822) and Horizon Europe, the European Union’s Framework Programme for Research and Innovation, under Grant Agreement No. 101070062 (SEQUOIA). Views and opinions expressed are however those of the authors only and do not necessarily reflect those of the European Union. The European Union cannot be held responsible for them.

Over the past 20 years optical frequency combs have been a powerful and enabling technology in the context of time and frequency measurement [1,2]. Their main claim to fame has been their cen-tral in the development of optical atomic clocks [3,4] and the realization of clock comparisons [5-7] to support redefinition of the SI second [6] and tests of fundamental physics [4-5]. Optical frequen-cy combs, based on modelocked lasers, combine ultrafast optical techniques and laser phase stabili-zation to permit coherent harmonic synthesis of atomic references across hundreds of terahertz in the optical domain [6]. Photo-mixing and nonlinear frequency conversion of the laser pulse train can be used to extend the synthesis range all the way to the XUV [7], to the MID IR [8], and down to the electronic domain [9], allowing for the realization of broadband synthesis across much of the electro-magnetic spectrum. The unique capabilities of optical frequency combs: low phase noise, low timing-jitter, spatial coherence, broad optical bandwidth, frequency resolution, efficient frequency conversion have led to a plethora of applications beyond atomic clocks. In my tutorial I will discuss how optical frequency comb sources are used for both precision optical and microwave synthesis and metrology and discuss their function and performance in the context of various time/frequency applications.

References
[1] Fortier T.M. and Baumann E., “20 years of developments in optical frequency comb technology and applica-tions,” Communications Physics 2, Article number 153 (2019).
[2] Diddams D.A., Vahala K., and Udem T., “Optical frequency combs: Coherently uniting the electromagnetic spec-trum” Science 369, 6501 (2020).
[3] Udem, T., Holzwarth, R. & Hänsch, T. W. Optical frequency metrology. Nature 416, 233–237 (2002).
[4] Ludlow, A. D., Boyd, M. M., Ye, J., Peik, E. & Schmidt, P. O., “Optical atomic clocks,” Rev. Mod. Phys. 87, 637–701 (2015).
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This conference presentation was prepared for SPIE Photonics West, 2024.

Whispering gallery mode resonators made from non-linear electro-optic materials are excellent platforms for frequency manipulation of electromagnetic radiation, allowing microwave up-conversion and the generation of frequency combs. By using an x-cut lithium niobate crystal to fabricate our WGM resonator, the resulting electro-optic coefficient varies around the circumference of the resonator, allowing for a simpler microwave geometry. We demonstrate a frequency comb with excellent repetition rate stability, and show results from dual combs with orthogonal polarisations. We measure the relative frequency stability of the dual combs, and find it to be 4 mHz, without any need for stabilisation or post processing. Besides these results at telecom frequencies, we will also show first results of a visible electro-optic frequency comb.

Following an analysis of the historical literature, we model the geometry of the original Stern–Gerlach experiment to numerically calculate the magnetic field using the finite-element method. Using the calculated field and a semi-classical model of spin, the propagation of the atoms in the beam is simulated to produce the well-known quantized end-pattern. Modeling the geometry of the magnets and the slits as faithfully as possible yields a two-dimensional pattern resembling the well-known postcard image sent by Gerlach to Bohr. The experimental parameters not reported in the original publications are ‘reversed engineered’ to adjust the length of the pattern.

The multi-stage Stern–Gerlach experiment conducted by Frisch and Segrè has been modeled analytically using quantum mechanics by Majorana and revised by Rabi by including the hyperfine interaction. However, the closed-form analytical predictions, which rely on approximations, do not match the experimental observation well. To avoid the approximations, we numerically solve the standard quantum mechanical model, via the von Neumann equation, which includes the hyperfine interaction for the time evolution of the spin. The outcome is compared with the experimental observation and the predictions by Majorana, Rabi, and an alternative model called co-quantum dynamics. Thus far, the coefficients of determination from the standard quantum mechanical model, which does not use free parameters, are still below zero. Non-standard variants that improve the match are explored.

The 1922 Stern–Gerlach experiment quickly proved fundamental to quantum physics. The benchmark experiment led to the quantization of angular momenta, discovery of electron spin, and study of the measurement problem and superposition. Immediately, Heisenberg and Einstein proposed multi-stage Stern–Gerlach experiments to explore deeper mysteries of directional quantization. In the classic multi-stage Stern–Gerlach experiment conducted by Frisch and Segrè, the Majorana (Landau–Zener) and Rabi formulae diverge afar from the experimental observation while the physical mechanism for electron-spin collapse remains unidentified. Here, introducing the physical co-quantum concept provides a plausible physical mechanism and predicts the experimental observation in absolute units without fitting (i.e., no parameters adjusted) with a p-value less than one per million, which is the probability that the co-quantum theory happens to match the experimental observation purely by chance. Further, the co-quantum concept is corroborated by statistically reproducing exactly the wave function, density operator, and uncertainty relation for electron spin in Stern–Gerlach experiments.

The Stern–Gerlach experiment stands as one of the fundamental demonstrations of quantum phenomena. A successive combination of Stern–Gerlach apparatuses was first explored as a gedankenexperiment by Heisenberg to study angular momentum quantization further; later a detailed experiment was proposed by Einstein to Stern and Ehrenfest. Here, we numerically study the spin flip in the Frisch–Segrè experiment, the first successful multi-stage Stern–Gerlach experiment, within the context of the novel co-quantum dynamics theory. Despite early attempts by P. Güttinger, E. Majorana, I.I. Rabi, L. Landau, C. Zener, and E. Stückelberg among others, theoretical descriptions deviate from the Frisch and Segrè observations. We model the middle stage responsible for spin rotation by sampling the atoms with the Monte Carlo method and solving the dynamics of the electron and nuclear magnetic moments numerically according to the Bloch equation. The simulated dynamics shows that co-quantum dynamics closely reproduces, without using any fitting parameters, the experimental observations reported by Frisch and Segrè in 1933, which have so far lacked theoretical predictions using the standard theories.

The 1922 experiment of Stern and Gerlach that initially provided evidence of the quantization of the angular momentum is now a prototypical example of quantum measurement. Frisch and Segrè in 1932 extended the experiment to include two Stern–Gerlach apparatuses separated by an inner rotation chamber, in which a varying magnetic field produces partial electron spin flipping. To this day, quantum mechanical treatments inadequately predict the experimental observations. Here, we use a theory termed co-quantum dynamics (CQD) to numerically model spin flip in the multi-stage Stern–Gerlach experiment conducted by Frisch and Segrè. Our simulation solves the Schrödinger equation with electron-nuclear interactions according to CQD and utilizes a branching condition (extended Pauli exclusion principle) postulated by CQD to predict the collapse of electron spins; the outcome agrees with the measurements of the fraction of spin flipping and supports CQD as a potential model for electron spin evolution and collapse.

Spin-specific trapping and mechanical control of ultracold atoms is difficult with current techniques, but offers the possibility of exploring new physics systems, such as spin-dependent trapped atom interferometers, as well as quantum gates, 1D many-body spin gases, and novel cooling schemes. Microwave near-field potentials based on the AC Zeeman effect provide a mechanism for such spin-specific control of atoms: in principle, independent potentials can be targeted to different spin states simultaneously. A broadband microwave atom chip can be used to generate both AC Zeeman trapping potentials and a microwave lattice for long distance trap positioning. We present recent experimental results on the successful trapping of ultracold rubidium atoms in an AC Zeeman atom chip trap using RF intra-hyperfine manifold transitions. Notably, these traps suppress the potential roughness encountered in traditional micro-magnetic chip traps.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

Many quantum applications require spectral multiplexed control to achieve the targeted high performances: for example, large band radiofrequency sensing and processing, high fidelity for quantum memories, or multi-qubits for quantum computing. We will discuss the main challenge involved by the spectral multiplexing: generating complex optical waveforms in VIS/NIR range. We will then focus in particular on rare earth ions, as they naturally offer a large inhomogeneous linewidth, tailorable by spectral hole burning, and discuss how to maintain the coherence of rare earth doped materials at cryogenic temperature under large band optical programming.

Trapped ions hold promise as the basis of highly accurate clocks and other quantum sensors. However, many real-world applications for quantum sensing require miniaturized, environmentally robust devices that can operate in the field. The significant experimental overhead imposed by free-space optics for control laser light delivery and collection has been an impediment to truly compact trapped-ion based clocks and sensors. The use of integrated technologies—including photonic waveguides, single-photon avalanche detectors (SPADs) and integrated electronics—provides a potential pathway towards overcoming these obstacles. I will discuss MIT Lincoln Laboratory’s recent efforts in this area, including demonstrations of integrated trapped-ion light delivery and collection and prospects for combining these technologies into a single chip-based trapped-ion reference.

This conference presentation was prepared for SPIE Photonics West, 2024.

Numerous precision metrology systems for detecting quanta of any kind are based on silicon detectors. One example are silicon detectors used in scanning electron microscopes (SEM) for electron detection. The need to investigate objects at the very near surface like e.g. cells in biology pushes the scientific progress for these silicon detectors. To study surface near regions of e.g. biological objects electrons with low energies around 500eV are necessary. Unfortunately, the quantum efficiency for such low energy electrons of state-of-the-art electron detectors is low or even non-existent. In this contribution the development of silicon electron detectors with large quantum efficiencies of more than 55% for electrons with an energy of 500eV is presented. The crucial steps in the development like the thin entrance window and a very shallow junction will be discussed and analyzed by simulation and experiments like secondary ion mass spectrometry (SIMS) measurements at CiS.

Magnetic sensors are widely used in many applications including medical diagnostics, geomagnetic survey, etc. Scalar atomic magnetometers that have demonstrated sensitivity at and below fT/ Hz^1/2 level can be adapted to include measurement of magnetic field orientation but usually at the cost of accuracy and with limitation of dynamic range. Magnetometry using electromagnetically induced transparency (EIT) instead was used to provide both scalar accuracy and vector information with angle resolution at a level of 10-3 deg/Hz^1/2. We present a scheme for EIT vector magnetic field measurement with the common-mode drift suppression by probing multiple EIT resonances. The demonstrated sensitivity is stable to < 200 pT/ Hz^1/2 at 1 mHz.

Recently, solid-state magnetometers have stimulated interest due to their smaller size, weight, and power compared to existing magnetometers, and their potential to self-calibrate; two features which improve the efficiency of any device carrying a magnetometer. In this work we simulate room-temperature ODMR of the negatively charged silicon vacancy VSi– in 6H-SiC, an emerging candidate for quantum magnetometry, using Lindblad master equations and density matrix populations and compare with experimental results. Furthermore, we simulate ODMR of VSi– V(2) site in isotopically-purified 6H-SiC, and predict superior sensitivity as compared with ODMR of samples with naturally-occuring magnetic nuclei.

We investigate spectral response of synchronous coherent population trapping (SCPT) to demonstrate its suitability for remote magnetometry as well as for vector magnetic field measurements. Remote magnetometry is demonstrated using fluorescence measurements in a sodium cell. A magnetometer with real-time, single-shot vector magnetic measurement capability, is also demonstrated using the SCPT effect produced in a small rubidium cell and by combining our experimental apparatus with a feedback system.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

We present a new class of ultra-low-loss torsion micropendula based on strain-engineered nanomechanics, and explore their application as parametric (clock) gravimeters. Specifically, by suspending a 0.1 mg Si paddle from a strained silicon nitride nanoribbon, we realize a 30 Hz torsion micropendulum with a damping rate of 20 micro-Hz, a parametric acceleration sensitivity of 6 Hz/g, and thermal acceleration noise of 3 ng/rtHz. By driving the pendulum into self-oscillation, we realize a clock gravimeter with a frequency stability as low as 50 parts-per-billion, corresponding to an acceleration resolution of 300 ng. Currently the limitation is the intrinsic nonlinearity of the pendulum, which transduces amplitude drift into frequency drift. We demonstrate how the duffing nonlinearity of the suspension can be used to cancel this nonlinearity, paving the way towards a fully isochronous, high-Q micromechanical clock.

The search for possible violations of Quantum Mechanics generally passes through tests of the principle of quantum superposition (interferometric experiments) or through tests of quantum nonlocality (violations of Bell's inequalities). Here we argue that a much more effective way to test the theory is through precise tracking of particle motion, even in classical states: this is because violations of quantum linearity must be random and as such make particles diffuse. We apply this strategy to test the collapse of the wave function, as well as the possible classical nature of gravity.

I will propose an on-chip dark matter search, sensitive to dark matter candidates with masses corresponding to optical and near-IR energies. Certain dark matter candidates, such as axion-like particles, can convert into photons within an appropriately designed optical structure. We consider an array of periodically-structured resonators which host dark matter to photon conversion. These photons are then collected and directed via waveguides onto single photon counters with low dark count, such as individual skipper CCD pixels. This setup allows a high collection efficiency, and is scalable to large resonator counts to increase both the total conversion rate and the dark matter mass sensitivity. A key challenge is to optimally combine many weak, phase-incoherent signals from these resonators onto one detector, which we address with free-space, spatial power combining and a detector covering a large solid angle. This search is able to probe both QCD axion dark matter and dark photons with mixing down to 1e-15.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

Thanks to their high tunability and ease of integration into microstructured devices, colloidal quantum dots (CQDs) have become a widespread building block in electro-optic technology. In order to translate this success into the realm of quantum science and technology, spectral stability and coherence, two closely linked topics, need to be addressed. In this talk, I will describe our recent effort in answering one of the fundamental questions in this regard: what is the underlying cause of spectral noise in the emission of CQDs? We embed CdSe/CdS core/shell quantum dots into microcapacitors and perform high-resolution photoluminescence spectroscopy of individual nanoparticles at cryogenic temperatures. Applying an external electric bias, we shift their emission wavelength and its sensitivity to spurious electric fields. Increasing this sensitivity, we observe a clear emhancement in the dynamic variance of the energy of the emitted photons. Fitting this result to a straightforward model, we provide direct evidence that microscopic stochastic electric fields are the root cause of spectral fluctuations in CQDs.

In this talk, I will present our latest results on performing nanoscale quantum sensing in living cells for reporting two parameters simultaneously: temperature and rheology. Temperature and viscosity are key parameters of interest that relate to cellular energetics and metabolism, morphological changes, cell division and active transport. The ability to correlate different parameters can help shed light on the development of cellular malfunction at the onset of a disease. We demonstrate the operation of a quantum sensor based on a diamond nanocrystal hosting nitrogen-vacancy centers in a living human cancer cell, extracting simultaneously information about the nanoscale temperature environment, the thermal and stochastic forces acting on the nanodiamond, and properties of its viscoelastic environment. I will also discuss the prospects of diamond-based quantum sensing for applications in healthcare. Gu et al., ACS Nano, 17, 20, 20034–20042 (2023)

We propose and experimentally demonstrate parallel light detection and ranging (LiDAR) using random intensity fluctuations from a highly multimode laser. We optimize a degenerate cavity to have many spatial modes lasing simultaneously with different frequencies. Their spatio-temporal beating creates ultrafast random intensity fluctuations, which are spatially demultiplexed to generate hundreds of uncorrelated time traces for parallel ranging. The bandwidth of each channel exceeds 10 GHz, leading to a ranging resolution better than 1 cm. Our parallel random LiDAR is robust to cross-channel interference, and will facilitate high-speed 3D sensing and imaging.

We present recent results on compact GaN based laser sources, primarily designed for cooling and trapping atoms and ions. We show various designs used for miniaturised, direct-generation laser sources in the UV-green part of the spectrum targeting multiple atomic species. We show results from a line narrowed 369nm ECDL for Yb+ cooling, a 397nm frequency stabilised source for Ca+ cooling and a 422nm butterfly packaged ECDL for Sr+ cooling.

Diamond containing the negatively-charged nitrogen vacancy colour centre (NV) is emerging as an important system for quantum sensing of various physical parameters including magnetic field and temperature. Here I will discuss the fabrication and characterization of an intrinsically magneto-sensitive optical fibre with potential applications as a high-efficiency remote magnetic sensing platform. The hybrid fibre allows for optical interrogation of NV-spin states via bound modes in a highly-stable waveguide structure. Our results open the possibility of robust, field-deployable fibre optical magnetometry for a broad range of quantum sensing applications.

Low noise dc electrical transport measurements provide a reliable means of characterizing the quality of the Josephson junctions (JJs) that form the heart of superconducting qubits. Measurements of the current-voltage (IV) characteristics can provide a direct readout of important junction parameters such as the Josephson energy Ej and the charging energy Ec. Here we report our investigation of an unexpected feature in the IV characteristics: the appearance of a finite resistance at currents below the critical current, where the resistance of the junction is expected to vanish. This “zero bias” resistance is observed in all the JJs that we have measured, fabricated by four different groups in the SQMS collaboration. The origin of this zero bias resistance and its potential implications for qubit performance will be discussed.

In this presentation, we will discuss advanced techniques to analyze the quantum states of single and multiple photons. Moreover, we will explore the use of super-resolution and full-field methods in quantum microscopy. Finally, we will examine the study of emitted photons by single-bubble sonoluminescence.

This conference presentation was prepared for SPIE Photonics West, 2024.

Presently, advancements in data handling, accompanied by a reduction in size, pave the way for emerging technologies like nanophotonics to complement existing information transport methods. The necessity for efficient photon and electron transport persists, despite its practical challenges due to varying scales. Optical properties, dictated by the conventional diffraction limit of light (usually in the hundreds of nanometres), pose compatibility issues with the prevalent scale of current microelectronics, typically in the tens of nanometres. This study proposes two distinct approaches to address this challenge. The first involves a hybrid plasmonic nanosystem featuring strategically positioned dual types of light-emitting nanosources on a silver nanowire electromagnetic waveguide. The second approach centers on integrating a single photon source with a photonic structure, utilizing a glass optical waveguide within photonics integrated circuits. We will provide examples of applications for quantum communications and quantum metrology.

The permanent electric dipole moment (EDM) of atoms, molecules, and elementary particles is predicted in the standard model. While it is too small compared with the experimental measurement sensitivity, it is an important method to search for beyond-standard-model physics via CP violating mechanisms. In this talk, I will focus on the EDM measurement of the 171Yb atoms with atoms held in an optical dipole trap. A quantum nondemolition measurement with a spin-detection efficiency of 50% is realized. A systematic effect due to parity mixing induced by a static E field is observed, and is suppressed by averaging between measurements with optical dipole traps in opposite directions. The coherent spin precession time is found to be much longer than 300 s. The measurement result leads to an upper limit of |d(171Yb)| < 1.5 E−26 e cm (95% C.L.). These measurement techniques can be adapted to search for the EDM of 225Ra.

Penning ion traps containing hundreds of ions held in a 2D crystal can be used to sense weak electric fields. We couple the crystal’s center-of-mass (CM) mode to the ions’ spin states, such that small perturbations of the crystal motion caused by external electric fields can be determined by measuring the spin precession. We have demonstrated a sensitivity to small displacements of 8.8 dB below the standard quantum limit (SQL), which enables an electric field sensitivity of 240 nV/m in 1 second. We plan to increase this sensitivity by parametrically amplifying the CM motion, which we expect to improve our sensitivity to displacements by a further 10 dB below the SQL. Supported by an appointment to the Intelligence Community Postdoctoral Research Fellowship Program, AFOSR grant FA9550-20-1-0019, by DARPA ONISQ, and by DOE, Office of Science, NQIS Research Center QSA

The Schrödinger equation, as a postulate, is a corner stone in quantum mechanics. The transition from classical physics to quantum mechanics, however, remains a mystery. In classical electrodynamics, the motion of the magnetic dipole moment of an electron is governed by the Bloch equation. Majorana stated that both the classical and the quantum-mechanical treatments on spin flip of atoms moving in a magnetic quadrupole field require integration of the same differential equations. Surprisingly, Majorana wrote the “Bloch” equation fourteen years before Bloch published his eponymous equation. Here, the classical Bloch equation for electron spin is mathematically converted to the space-independent von Neumann equation for a pure state of a two-level spin system. Subsequently, the space-independent Schrödinger–Pauli equation is derived in both frameworks of quantum mechanics and recently developed co-quantum dynamics. Therefore, the inverse conversion is shown, and the two-way transitions for a pure state of electron spin between the classical Bloch equation and the space-independent Schrödinger–Pauli equation are established.

The design, fabrication and characterisation of a silicon nitride optical phased array (OPA) for waveguide integration with flip-chip bonded rubidium (Rb) atomic MEMS vapour cells are demonstrated. A one-dimensional OPA with a symmetric splitter tree design at 780 nm wavelength is fabricated by electron-beam lithography and plasma dry-etching. The waveguides were cladded with silicon dioxide before bonding to an Rb MEMS vapour cell. The characterisation was performed by end-fire coupling a 780.24 nm laser to the waveguide by a lens fibre. A saturated absorption spectroscopy measurement revealed the ~ 6 MHz hyperfine transition absorption dips that can be utilised for laser frequency stabilisation for atomic cooling.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

In this presentation I will introduce a new approach to control the quantum state of a macroscopic mechanical resonator via measurement and conditioning. By operating in the fast measurement regime, we show that it is possible to prepare quantum squeezed states of motion. Remarkably, our theory predicts that the experimental requirements are greatly relaxed, even compared to mechanical ground-state cooling, to the point that quantum state preparation is feasible at room temperature with existing technology. I will present experiments showing a classical version of the predicted squeezing effect in a new engineered double-disk optomechanical device fabricated on a silicon chip. These experiments take advantage of both structural damping – which we show that, compared to the usual viscous damping, can improve quantum state preparation – and arrays of mechanical modes. Specifically, I will present experiments demonstrating that continuous position measurement can prepare thermomechanical squeezed states of motion, and to this for ensembles of structurally damped mechanical resonances.

Bell inequalities are one of the cornerstones of quantum foundations and fundamental tools for quantum tech. [1], tied to specific aspects of quantum mechanics, as quantum non-locality [2]. We present here the first single-pair Bell inequality test [3] able to obtain a Bell parameter value for every entangled pair detected. This is made possible by exploiting sequential weak measurements, allowing to perform non-commuting measurements in sequence on the same state, on each entangled particle. Such a feature grants unprecedented measurement capability. We also demonstrate how, after the Bell parameter measurement, the pair under test still presents a noteworthy amount of entanglement, providing evidence of the absence of the wave function collapse and allowing us to exploit this quantum resource for further protocols. We will discuss possible applications. [1] M.Genovese, Physics Reports 413 (2005) 319 [2] M. Genovese, M. Gramegna, Applied Science 9 (2019) 5406. [3] S.Virzì, et al. arXiv:2303.04787

Diamond color centers like the nitrogen-vacancy (NV) have shown much promise for nanoscale sensing of magnetic and electric fields and temperature. So far however the quantum properties of the NV have not been used to full advantage, for example quantum entanglement of NV qubits has rarely been used for sensing. In this talk I will review recent advances in the fabrication of NVs, and other magnetic color centers in diamond, and in the growth of high quality nanodiamonds. Combining these advances, I will discuss the future prospects of engineering quantum-enhanced sensors in nanodiamonds.

We report on use of coverslip-based microwave antenna as an experimental platform for quantitatively characterizing NV spin properties of different types of fluorescent nanodiamonds (NDs). This coverslip antenna provides as-designed magnetic field of microwaves for spin excitation, thereby precisely determining NV spin relaxation times (T1, T2) of conventional type-Ib NDs and 12C-enriched NDs. Furthermore, we demonstrate measurements of the spin relaxation times inside live cells (HeLa and HepG2). We discuss potential applications of 12C enriched nanodiamonds for biologicals sensing with our coverslip antenna devices.

Surface acoustic waves (SAWs) support long group delays and analog signal processing as part of electronic circuits for decades. SAWs may also be introduced to integrated silicon photonic circuits, through thermo-elastic actuation: the absorption of modulated pump light in gratings of metallic elements. Microwave-rate information is thereby converted from the modulation of an optical carrier to heat representation, and then to SAWs. Information is recovered in the optical domain through photo-elastic modulation of a second carrier wave in a standard silicon-photonic circuit. The biggest drawback of the SAW-photonic integrated devices is the relative inefficiency of thermo-elastic actuation, which leads to large losses of microwave-frequency electrical power between input and output: on the order of 70 dB. In this work, we report the enhancement of actuation through surface-plasmon resonance effects. The metallic grating elements are split to resonant unit cells, designed for maximum absorption of pump light. End-to-end power losses are reduced to only 48 dB. The results highlight the prospects of SAW-photonics as potential platform for integrated signal processing

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

This conference presentation was prepared for SPIE Photonics West, 2024.

Interferometers are highly sensitive measurement devices that map phase changes into intensity changes. Those classical interferometers have a sensitivity limit that cannot be beaten by classical approaches. SU(1,1) interferometers can surpass that shot-noise limit and improve the sensitivity by quantum approach of employing squeezed states of light and destructive interference of the noise. We developed and demonstrated a temporal SU(1,1) interferometer by utilizing two time lenses in a 4f configuration. We achieved three advantageous in addition to the improved sensitivity of SU(1,1) interferometers; The first one is the high temporal resolution we reach by applying time lenses. The second is simultaneously measuring interference in time and frequency domains in single shot measurement. Third, our temporal SU(1,1) interferometer is sensitive to the phase derivative and can detect ultrafast phase changes.

This conference presentation was prepared for SPIE Photonics West, 2024.

Nuclear magnetic resonance with nitrogen-vacancy centers in diamond (nano-NMR) can provide room-temperature detection of weak magnetic fields originating from nuclear spins in samples at nanometer scale. Noise originated from the sample and device cause broadening of the spectral lines and is one of the main limitations in the frequency resolution in non-polarized nano-NMR measurements. In this work, we describe the impact of these noise sources on the device’s overall sensitivity from simulations of the decoherence and spin dephasing of the NV center via Lindblad equation solutions

This conference presentation was prepared for SPIE Photonics West, 2024.

The spatial degree of freedom of entangled beams of light offers unique opportunities for quantum information due to its large dimensionality. Here, we show that it is possible to tailor the distribution of the spatial quantum correlations in entangled twin beams by taking advantage of the phase matching properties of four-wave mixing. This control can enable high-capacity quantum channels and quantum-enhanced spatially resolved sensing and imaging.

We discuss applications of quantum molecular coherence, as well as nonclassical states of light, such as entangled and squeezed light, to improved molecular spectroscopic sensing. We consider scenarios ranging from remote to near-field configurations, where enhanced sensitivity and resolution are further aided by plasmonic nanostructures and antennas.

We are investigating coherent population trapping (CPT) and Ramsey-CPT interrogations in a cold atom system where the atomic beam originates from a pushed two-dimensional magneto-optical trap (2D+-MOT). Our results show promise for improving the performance of atomic clock using a cold atomic beam apparatus.