The emerging class of photomechanical materials are enabling new types of optical devices. Here, we will present mechanical devices based on fiber-integrated photomechanical materials. When illuminated, a volumetric change is created in the active photomechanical material, causing a mechanical response from the fiber. In this presentation, we will discuss the modeling, design, fabrication, and testing of this novel system.

Silicon Nitride photonic integrated circuits are highly sought after for quantum applications. This platform offers ultra-low propagation losses, reduced birefringence, and a wide transparency window. This study presents the design and experimental demonstration of a compact silicon nitride polarization beam splitter (PBS) for the 950 nm wavelength range. The PBS employs cascaded tapered asymmetric directional couplers to achieve efficient polarization control. With insertion losses below 1 dB, polarization extinction ratios exceeding 19 dB (TE) and 10 dB (TM), and operation from 920 nm to 970 nm, it offers promising integration into photonic systems requiring precise polarization manipulation.

A significant fraction of North American rivers and streams are becoming salter and this has a variety of negative environmental and socio-economic consequences. Improving our ability to monitor water quality remotely is highly desirable. Combining Brillouin spectroscopy and LIDAR was been suggested to be a promising avenue for airborne or spaceborne temperature profiling of oceans, but much work remains to be done. We propose to employ VIPA-based Brillouin spectrometers to monitor salt concentration in rivers, streams, and pounds remotely from unmanned aerial vehicles. We present preliminary remote sensing measurements from 2 m away in which we measure the concentration of sodium chloride with a precision on the order 1 g/L. We also present simulations of a depth-resolving confocal scheme, demonstrating <0.5 m axial resolution from 50 m altitude. Finally, we demonstrate the ability to measure Brillouin spectra on a vibrating platform.

Coherent LiDAR is a highly sensitive sensing technology with immunity to ambient light interference and the ability to measure velocity. It emits a wavelength-swept light signal and calculates the beat frequency between reference and sample light to measure the distances of targets. Recent advancements in signal modulation techniques, particularly quadrature detection, have effectively improved the detectable range of coherent LiDAR. In this study, we employ a 4x4 coupler for quadrature detection and incorporate dual reference paths with varying optical delays through an optical switch. This approach achieves a fourfold range extension compared to the conventional setup, while utilizing the same laser source and data acquisition process.

Coherent light detection and ranging (LiDAR) system is widely used to measure distance. Distance and velocity measurements are important in many industries, including autonomous vehicles. However, conventional coherent LiDAR systems has limitations in measuring distance and velocity due to laser coherence length and frequency ambiguity. In this study, through wavelength division multiplexing, multi-interferometer was used to overcome these limitations. To solve the frequency ambiguity in this system, a novel method of frequency decoding is utilized. By applying the frequency decoding to our system, we can address the issues associated with proposed coherent LiDAR.

We demonstrate a system based on dual-comb LiDAR that can measure absolute distances at a high update rate of 7.7 kHz in real-time. This is enabled by a novel LiDAR frontend combined with a GPU-accelerated algorithm, which allows for real-time reconstruction of the target’s position. We track the movements of a retroreflector attached to a trolley on a comparator bench at distances of around 35 m and 50 m for 10 s. Comparing the relative measurements to a reference Doppler interferometer, we find that we can track the target’s motion with micrometer-level residual errors, even over these long distances.

We present a novel computational camera with high spatial, spectral, and temporal resolution as a practical tool for real-world applications in VIS-NIR hyperspectral (HSI) video imaging. Hyperspectral images contain orders of magnitude more information than colour (RGB) images and promise to reveal new insights in many application domains. However, widespread adoption of HSI has been hindered by the performance limitations of imaging equipment, complexity of application development and costs of deployment. We report on a compressed sensing approach using a variation of coded aperture snapshot spectral imaging (CASSI) with low aberration dispersive optics to capture the multiplexed projection of spatial-spectral scene information on standard CMOS technology. We overcome the typically slow computations associated with CASSI signal reconstruction and report state-of-the-art performance using machine learning methods for signal unmixing at speeds enabling live processing on networked NVIDIA gpu-enabled platforms. Contemporary applications and the motivation for packaging as a computer vision development kit are discussed.

We present a novel wide-field Raman microscope, based on the time-domain Fourier-transform method. This enables parallel acquisition of Raman spectra on all the pixels of the 2D detector; the resulting wide-field approach allows faster collection of Raman maps with respect to standard raster-scanning methods. In addition, the time-domain method disentangles fluorescence and Raman signals. The system is robust and stable, thanks to the use of an ultrastable common-path birefringent interferometer. Validation of the system is performed on plastic microbeads and on a few-layers transition metal dichalcogenide sample.

We introduce the traceable calibration of a cryogenic localization microscope, enabling accurate localization of quantum dots to improve subsequent integration into photonic cavities. We combine the calibration results with an assessment of fabrication accuracy by electron-beam lithography to introduce a comprehensive model of the effects of registration errors in the integration process on Purcell factor. Our theory shows the possibility of significantly improving the magnitude and distribution of Purcell factor across a wide field, enabling dramatic increases of process yield.

We present a new high resolution design of FPGA-based Time-Correlated Single Photon Counting (TCSPC) and time tagging electronics with multiple synchronized input channels. The new instrument achieves a state-of-the-art digital time resolution of 1 ps and a single channel timing uncertainty of 2 ps rms along with an ultra short dead-time. This unprecedented combination enables new high-resolution TCSPC applications and significantly improves the resolution of the established high-speed fluorescence lifetime imaging method RapidFLIM. In oder to support the widest possible variety of single photon detectors the new instrument provides software-configurable input circuitry. For optimal timimg with e.g. Superconducting Nanowire Single Photon Detectors (SNSPD) the inputs can be configured as edge triggers while for best performance with Hybrid Photodetectors (HPD) or Micro Channel Plates (MCP) they can be configured as vertex finding Constant Fraction Discriminators (CFD). Apart from design features and benchmark results of the instrument as such, we present results from fast fluorescence lifetime imaging and some snapshots of other applications.

Optical substrates with parallel surfaces are widely used in todays photonics devices. Whether they have flat (screens, filters, beamsplitters, crystals) or spherical (such as optical domes) surfaces, the metrology of such objects is complicated as they can cause unwanted interference which compromise the precision of the optical metrology performed. We have developed a new instrument whose optical path is similar to that of Fizeau-type interferometers, but which uses a light source with low temporal coherence. This implementation brings to main advantages: it avoids the generation of interference generated by the back surface of the thin-plane parallel optics to be tested; it provides a significant degree of freedom when it comes to choosing a wavelength of test. This makes it possible to characterize optical components independently of their thickness, spectral transmission and coatings. In this communication, we will detail the method developed and compare it with other wavefront sensing solutions. We will present results obtained on different samples and discuss the promise of this solution for manufacturing testing, whether for in situ process control or end-of-line testing.

We introduce a compact hyperspectral camera based on the time-domain Fourier-transform approach, equipped with an ultrastable birefringent interferometer. The time-domain approach enables hyperspectral imaging with shorter acquisition times and higher spectral accuracy compared to standard dispersive optics. We provide experimental proofs of the camera capability by performing remote-sensing measurements in the visible and near-infrared range. Recently we extended the spectral range to the thermal infrared, where vibrational transitions associated with chemical bonds have their absorption. Due to its compactness, lightweight and extreme stability even in harsh environments, the camera is a unique enabling technology for remote unambiguous chemical identification.

Hyperspectral imaging is rapidly advancing and transforming industries such as agriculture, medicine, and defense. The introduction of HERA, a new hyperspectral camera, is a notable development in this field. Utilizing a Fourier-transform approach, HERA consists of a monochromatic camera, camera lens, and an innovative common-path birefringent interferometer. By scanning the interferometer's position and capturing a sequence of monochromatic images, the hyperspectral data-cube is acquired without any camera or sample movement. This approach offers advantages like high light throughput, signal-to-noise ratio, and wavelength accuracy. HERA's exceptional light throughput enables high-quality data even in low-illuminance conditions and fluorescence studies. Additionally, its flexibility and stability allow for integration with commercial microscopes, expanding the applications of hyperspectral imaging to the microscopy field. This work focuses on showcasing HERA's significant applications in microbiology.

FMCW-LiDAR (Frequency-modulated continuous wave - Light detection and ranging) measures object distance by measuring the temporal interferogram with frequency-swept laser beams. However, to capture 3D scenes, most current FMCW-LiDARs rely on raster scanning of the laser beam, which compromises either image resolution or volumetric frame rate. In this work, we present a scanning-free FMCW-LiDAR by introducing a computational imaging framework. Specifically, the 3D scene is captured using a one-dimensional linear sensor integrated with a series of lens and prism arrays. Additionally, we employ the compressed sensing principle, enabling us to efficiently capture high-resolution 3D scenes.

In this study, a multi-channel beam scanning of a coherent LiDAR (light detection and ranging) system was developed using WDM (wavelength division multiplexing) to overcome the limitations of the conventional single-beam approach, particularly its lower imaging speed. The experimental setup involved adding a WDM module to a Mach-Zehnder-type fiber-based interferometer. The original beam was divided into beams with different center wavelengths using WDM. These beams are directed at the target with a 1D Galvo scanner to build the x-y image. Interference signals between sample and reference lights were analyzed by each individual channel, enabling distance calculations through a fast Fourier transform. The proposed system with multi-channel beam scanning successfully improved scanning speed and obtained 3D images.

For frequency modulated continuous wave (FMCW) light detection and ranging (LiDAR), which is long-distance 4D measurement technology, fast Fourier transform (FFT) is necessary which requires high-performance computing devices. As the measurement target moves away, the measurable distance is limited by the increased beat frequency and coherence length of the light source. In this study, time-domain coherent LiDAR system was designed using chirped fiber Bragg grating (CFBG) at the reference arm. The proposed technology can measure distance without FFT and regardless of the coherence length of the light source. We acquired distance information and 3D images of targets over 10 meters.

Probing the suspended particles in natural water is significant for environmental monitoring and ecological research, such as early warning of water blooms and assessment of water quality. The particulate Mueller matrix polarimetry (PMP) based on polarized light scattering is established, which can be used to obtain the physical properties and polarization features of individual suspended particles in water. Previous researchers have measured the bulk Mueller matrix of water, in order to obtain information on suspended particles. However, there are many different suspended particles in the water, and the bulk Mueller matrix of water is difficult to know the properties of each particle and precisely retrieve the specific proportions of target suspended particles in the water. Recently, PMP can individually measure the suspended particles, and unlocks the potential of the Mueller matrix for the recognition and characterization of individual suspended particles in water. Powered by machine learning, many experimental results prove the potential abilities of PMP for the in-situ recognition and concentration proportions monitoring of different suspended particles in water.

This study presents a non-destructive crack detection method for electronic devices using photoacoustic ultrasound. By utilizing a black ink film as a photoacoustic signal generator, cracks can be located and mapped with high precision. The technique uses the black ink film of the product and can detect small cracks of about 40 μm using a laser beam. This approach offers numerous industrial applications, enabling manufacturers to assess device condition, locate defects, and improve product quality without causing further damage. It has the potential to enhance user satisfaction by reducing malfunctions in electronic devices.

In this study, we introduce a measurement system based on DS-PAM (dichroism-sensitive photoacoustic microscopy) for assessing quench cracks. We evaluated a quench crack sample with dimensions of 300 μm in width and 150 μm in depth. Our observations revealed the presence of dichroism specifically at the edges of the crack.