This PDF file contains the front matter associated with SPIE Proceedings Volume 12870, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

This manuscript introduces and shares MATLAB code for simulating the behavior of a temporal SU(1,1) interferometer, offering a valuable resource for researchers and practitioners in the field. The provided code facilitates comprehensive simulations of the interferometer’s dynamics, enabling the exploration of its response to various parameters and scenarios. The simulations delve into the interferometer’s performance, emphasizing its sensitivity to ultrafast phase changes and its concurrent operation in both the time and spectral domains. By making the MATLAB code openly available, this contribution aims to foster collaboration, enhance reproducibility, and serve as a foundational tool for researchers delving into the design and analysis of temporal SU(1,1) interferometers. The manuscript provides detailed documentation on code usage, empowering users to adapt and extend the simulations for their specific research inquiries.

Time-stretch spectroscopic method, employing chirped optical pulses, has significant attention due to its remarkable spectral acquisition rate. However, its application is limited due to the low light throughput and narrow bandwidth of previous time-stretching systems. We present a high-power time-stretch near-infrared (NIR) light source, leveraging Arrayed Waveguide Gratings (AWGs), designed to overcome these limitations. This novel configuration utilizes AWGs and short optical fibers to achieve significant chromatic dispersion with high throughput, yielding output power of 90 mW and spectral width of 400 nm. As a result, we clearly observed the absorption spectra for low transmittance samples within a millisecond. This represents a significant step forward for transmittance based industrial NIR spectroscopy applications.

Time-stretch spectroscopy has the potential for high-speed inspection application. Currently, the low output power of chirped pulses limits the throughput and targets. We applied Arrayed Waveguide Gratings (AWGs) to time-stretch spectroscopy and achieved a high output power of 90 mW, which is about ten times higher than conventional method. In this study, we performed Near-Infrared (NIR) spectroscopy of low-transmittance samples with the developed time-stretch spectrometer. The absorbance spectrum of liquid samples was measured within ⪅1 ms/sample even with an optical attenuation by an ND filter (OD 3.8). In addition, we can estimate the volume fraction of highly scattering samples with a high accuracy (R² = 0.996) in approximately 5 ms. This result demonstrates the potential of our spectrometer for quantitative spectral analysis of highly scattering samples.

We introduce a novel method of isolating carrier dynamics in optically excited semiconductors using optical-pump terahertz-probe spectroscopy, with a large external magnetic field to isolate different carrier types based on their cyclotron energies. We employ new echelon-based single-shot detection that utilizes a pair of 1D line array detectors which can read out at a 1 kHz repetition rate, reducing acquisition time by more than an order of magnitude. This enables collection of full 2D optical-pump/THz-probe scans at different magnetic fields. We demonstrate these capabilities by performing cyclotron resonance measurements in bulk silicon, and discover distinct carrier dynamics for electrons and holes, as well as their dependence on an external magnetic field.

Beam monitoring of relativistic charged particle beams is of great interest for various applications including a high-order harmonic generation-seeded free-electron-laser. In particular, in phenomena with low repeatability/reproducibility such as laser-plasma acceleration experiments, it is important to measure spatio-temporal density profile of accelerated charged particle beams in a single shot. In this research, single-shot ultrafast spatio-temporal density profile measurement of relativistic electron beams in radiofrequency accelerators is conducted via obtaining spatio-temporal electric-field profile around the beams with combination of electro-optic sampling and echelon-based single-shot method. Here, we introduced an analytical model derived by special relativistic electromagnetism to deduce longitudinal and transverse beam sizes by measured spatio-temporal electric-field profiles.

Real-time imaging of ultrashort events on picosecond timescales has proven pivotal in unveiling various fundamental mechanisms in physics, chemistry, and biology. Current single-shot ultrafast imaging schemes operate only at conventional optical wavelengths, being suitable solely within an optically transparent framework. Here, leveraging on the unique penetration capability of terahertz radiation, we demonstrate a single-shot ultrafast imaging system that can capture multiple frames of a complex ultrafast scene in non-transparent media with sub-picosecond temporal resolutions. By multiplexing an optical probe beam in both the time and spatial-frequency domains, we encode the terahertz-captured dynamics into distinct spatial-frequency regions of a multiplexed optical image, which is then computationally decoded and reconstructed. Our approach opens up the investigation of non-repeatable or destructive events that occur in optically-opaque scenarios.

Recent advances in single-shot detection in ultrafast spectroscopies have dramatically expanded the applicability of nonlinear and multi-dimensional ultrafast spectroscopies to previously unexplored regions of the spectrum as well as to novel dynamical and physical and chemical processes. Unlike traditional pump-probe detection schemes, where the pump-probe time delay is obtained using mechanical delay stages, single-shot detected experiments employ a mechanism where dynamical information about a process in a sample may be captured with femtosecond time-resolution for the entire duration of the event, (up to ten’s of picoseconds), and read out within a single-shot. The benefits of single-shot detection include up to orders of magnitude reduction in experimental acquisition times, the potential to measure irreversible processes, and the ability to reduce unwanted nonlinear effects by using modest pump excitation energies. We discuss the performance characteristics of modern scientific Complementary Metal Oxide Semiconductor (sCMOS) cameras that make them well-suited detectors for these experiments; a highly parallel pixel readout mechanism resulting in fast frame rates with low read noise, high quantum efficiency for optical detection, excellent linearity, high dynamic range and flexible pixel binning. Recent experiments implementing sCMOS technology for this detection scheme, such as single-shot detected nonlinear Terahertz Kerr Effect (TKE) spectroscopy and broadband Single-Shot Transient Absorption spectroscopy (SSTA), are reviewed.

Existing position sensors have limitations such as single function, limited range, slow speed, and low resolution. Emerging applications need sensors that work in variable and unpredictable environments with multiple dimensions. The proposed system offers advantages that outweigh these existing sensors. It has a unique design that combines optical imaging and laser techniques to provide a full capability of 6-dimensional sensing with only one sensor system, covering a wide range for both near and far fields with both high spatial and angular resolutions. The sensor can also easily extend its capability by modifying optics and laser or exploiting new optical components. In addition to the above six degrees of freedom, the sensor has potential to detect additional information such as the speed and acceleration of the target for both linear translation and rotation, by simply record the time lapse between events. Therefore, our technique has broad potential applications. It can also facilitate technical advances in metrology, biomedicine, and scientific research.