Photonic quantum technologies are a promising platform for a large variety of applications ranging from secure long-distance communications to the simulation of complex phenomena. Among the material platforms under study, semiconductors offer a wide range of functionalities opening several opportunities for the development of integrated quantum photonic circuits. AlGaAs is particularly attractive to monolithically integrate active and passive components since it combines high second order nonlinearity, electro-optic effect and direct bandgap. In this talk, I will present the work of our team on the generation of quantum states of light in the telecom range with nonlinear AlGaAs chips working at room temperature. The talk will review recent developments on monolithic and hybrid integrated devices, describe the versatility of these systems for the generation and manipulation of quantum frequency states and show their potential for the implementation of flexible entanglement-distribution networks for secure communications.

In this talk, we will discuss our recent progress in simulating condensed matter physics phenomena with a quantum-correlated synthetic crystal produced on chip.

The unique behavior of quantum systems, such as coherence, superposition, and entanglement, can be harnessed to process, encode, and transmit information. Each quantum application (communication, computing, metrology, sensing, etc.) places its own set of requirements on the underpinning photonic technology, but many of these requirements are common to all the applications, and they form the basis for the implementation of future silicon quantum photonic integrated circuits (SiQuPICs). These common elements include single- or entangled-pair photon sources, passive optics to coherently mix photonic modes, active optics and delay lines to reconfigure those modes, high extinction ratio filters, and single-photon detectors. In this paper, we describe the design and fabrication of a basic SiQuPIC, comprising single-photon or entangled-photon-pair sources coupled to passive optical waveguides ending with single-photon detectors, all integrated on a single Si chip.

Spectrometer based on SPAD linear array with sub-nanosecond timing resolution and single photon sensitivity for quantum-assisted optical interferometers. A.Nomerotski, P.Stankus, M.Keach, B.Farella, J.Crawford, R.Abrahao (BNL) E.Charbon, S.Burri, C.Bruschini, E.Bernasconi (EPFL) S.Kulkov, J.Jirsa, M.Marcisovsky (Czech TU) Improved quantum sensing of photons from astronomical objects could provide high resolution observations in the optical benefiting numerous fields in astrophysics and cosmology. It has been recently proposed that stations in optical interferometers would not require a phase-stable optical link if instead sources of quantum-mechanically entangled pairs could be provided to them, enabling extra-long baselines, and potentially improving the astrometrical precision by orders of magnitude. The basic observational event will be the registration of two photons in the system close enough together in time and frequency to be in the same temporal mode, and so be indistinguishable. This will require spectrometers with sub-nm spectral and sub-ns timing resolution with single photon sensitivity. In this contribution we describe a possible design of such a spectrometer and its characterization.

Microlenses, and especially microlens arrays (MLA), are commonly used as stand-alone optical components, for beam homogenization and shaping. Or integrated as wafer-level optics (WLO), either on top of light sources for beam shaping (e.g., on micro-LED or vertical-cavity surface-emitting laser – VCSEL), or on top of light or image sensors as light concentrators. In the latter case, each microlens of the MLA, also known in the photography domain as On-Chip Lens (OCL), redirects the light to the active volume of the pixel located underneath. This increases the external quantum efficiency (EQE) by increasing the pixel effective fill-factor, especially for front-illuminated image sensors and their limited fill-factors. We report various MLA optimizations and the concentration factors achieved when addressing challenges encountered with advanced photon detectors such as single-photon avalanche diodes (SPAD) or silicon photon multiplier (SiPM). For example: substrate size and type (wafer, bare or packaged die), optical transmission range from NUV to NIR, microlens geometrical parameter space (diameters from micrometers to millimeters) and stability to temperature, vibrations and irradiation (UV, gamma and proton).

The cohort of companies and researchers working on a broad variety of technologies quantum information processing has grown dramatically in recent years. Novel research in the field of quantum photonics, in particular, is exciting and is seeing an increase in the number and scope of applications. In this talk I will give some background on Quantum Opus as a leader in providing advanced photon detection systems for research markets, including a state-of-the-art view of Superconducting Nanowire Single-Photon Detector (SNSPD) technologies, cryogenic and electro-optic developments, and what we see as the significant emerging quantum and non-quantum markets for superconducting photon detectors. These new markets include free-space communication, medical applications, and atmospheric sensing. Additionally I will explain some of the ways in which we have successfully balanced research with commercial product development through grants, collaborations, and joint commercial developments.

We present the results from testing the performance of CdZnTe (CZT) position-sensitive virtual Frisch-grid (VFG) detectors for gamma-ray imaging. Large-volume CZT detectors with dimensions up to 10x10x30 mm3 recently became available from CZT crystal vendors. Such devices improve detection efficiency and position resolution when integrated into position-sensitive photon counting cameras proposed for nonproliferation, nuclear security, and gamma-ray astronomy. It is important to evaluate the factors affecting the response uniformity and limiting the performance of these detectors. In general, the response non-uniformities could be caused by detector geometries, materials inhomogeneity, and crystal defects. Several techniques have been developed to correct response non-uniformities and improve detector performance. Among them are the high-granularity position-sensitive detectors, which provide the most accurate and robust corrections. Position sensitivity can also be used to reveal response non-uniformities and understand their causes during the detector development or fabrication stages. Here, we describe a technique that we developed for position-sensitive virtual Frisch-grid detectors employing CdZnTe (CZT) and other semiconductors. To illustrate our experimental technique, we measured responses from the selected detectors of different qualities acquired from different vendors and grown by different methods.

Here we establish a platform for efficient electron-photon pair generation by integrating a photonic chip-based silicon nitride microresonator into a transmission electron microscope. The free electrons passing the resonator scatter inelastically with the empty optical modes, leading to a quantized electron-energy loss as well as the generation of cavity photons. The temporal correlation of their detection demonstrates the generation of electron-photon pairs. Selection of these pairs allows further analysis of the generation process, as well as the usage of the platform as a high-fidelity single-photon or single-electron source. This promises new experimental capabilities in free-electron quantum optics.