Non-line-of-sight (NLOS) imaging has recently attracted a lot of interest from the scientific community. The goal this paper is to provide basis for comprehensive mathematical framework NLOS that directly derived physical concepts. We introduce irradiance phasor field (P-field) as an abstract quantity fluctuations, akin complex envelope Electrical (E-field) used describe propagation electromagnetic energy. demonstrate P-field propagator analogous Huygens-Fresnel describes other waves and...

Various existing target ranging techniques are limited in terms of the dynamic range operation and measurement resolution. These limitations arise as a result particular methodology, finite processing capability hardware components deployed within sensor module, medium through which is viewed. Generally, improving adversely affects its resolution vice versa. Often, distance designed for an optimal range/resolution setting depending on intended application. Optical triangulation broadly...

The non-line-of-sight (NLOS) imaging problem has attracted a lot of interest in recent years. objective is to produce images objects that are hidden around corner, using the information encoded time-of-flight (ToF) photons scatter multiple times after incidence at given relay surface. Most current methods assume Lambertian, flat and static surface, with non-moving targets scene. Here we show NLOS reconstructions for surface non-planar rapidly changing during data acquisition. Our system...

Non-line-of-sight (NLOS) imaging systems involve the measurement of an optical signal at a diffuse surface. A forward model encodes physics these measurements mathematically and can be inverted to generate reconstruction hidden scene. Some existing NLOS techniques rely on illuminating surface measuring photon time flight (ToF) multi-bounce light paths. Alternatively, some methods depend high-frequency variations caused by shadows cast occluders in While models for ToF-NLOS Shadow-NLOS have...

The depth resolution of a continuous-wave time-of-flight (CW-ToF) imaging system is determined by its coding functions. Recently, there has been growing interest in the design new high-performance CW-ToF However, these functions are typically designed hardware agnostic manner, i.e., without considering practical device limitations, such as bandwidth, source power, digital (binary) function generation. Therefore, despite theoretical improvements, implementation remains challenge. We present...

Time-of-flight (ToF) non-line-of-sight (NLoS) imaging reconstructs images of scenes with light that have undergone diffuse reflections. While, in the past, ToF propagation and reconstruction methods been described using their own inverse methods, it has recently shown transport can be as a wave, allowing to modeled by same are applied for direct electromagnetic or sound waves. This wave fluctuating optical irradiance is called phasor field (P-field) wave. Here, we perform series experiments...

Thin film samples like transparent conducting oxides (TCO) are typically investigated using measurements Hall Effect and 4-point probe measurements. We use a sensitive AC Faraday rotation (FR) setup to study thin for which magneto-optic response is challenging characterize. The experimental employs stabilized He-Ne laser (633 nm) along with an magnetic field that enables lock-in detection. investigate series of TCO deposited on glass substrate. include the more widely used Indium Tin Oxide...

The fundamental Gaussian TEM00 mode is the most common of propagation within various optical devices, modules, and systems. Beam profilers are widely used in accurately ascertaining cross-sectional irradiance profile a for free-space communication systems as well tracking beam evolution when propagating submodules. We demonstrate profiling methods that use low-cost, off-the-shelf, available circular apertures such irises spatial filters. In order to with any aperture, we first derive exact...

This paper presents a motion-free technique to characterize the focal length of any spherical convex or concave lens. The measurement test-bench uses Gaussian laser beam, an electronically controlled variable focus lens (ECVFL), digital micro-mirror device (DMD), and standard photo-detector (PD). method requires measuring beam spot sizes for different settings ECVFL using data obtain estimate through iterative least-squares-based curve-fitting algorithm. is also shown overcome potential...

This paper presents a novel approach to simultaneously measuring the thickness and refractive index of sample. The design uses an electronically controlled tunable lens (ECTL) microelectromechanical-system-based digital micromirror device (DMD). method achieves desired results by using DMD characterize spatial profile Gaussian laser beam at different focal length settings ECTL. ECTL lensing through minimal motion liquid inside transparent casing, whereas contains array movable micromirrors,...

To the best of authors knowledge, proposed is first variable fiber-optical attenuator (VFOA) using a digital micromirror device (DMD) and an opto-fluidic electronically controlled focus lens (ECVFL). The hybrid VFOA uses individually controllable two-state micromirrors DMD focal length capability ECVFL to control amount light coupled between two fiber ports leading high dynamic range VFOA. demonstrated at 1545 nm has 63.5-dB range, <0.1-dB resolution, 0.2-dB polarization-dependent loss,...

Non-Line-of-Sight (NLOS) imaging allows to observe objects partially or fully occluded from direct view, by analyzing indirect diffuse reflections off a secondary, relay surface. Despite its many potential applications, existing methods lack practical usability due several shared limitations, including the assumption of single scattering only, occlusions, and Lambertian reflectance. We lift these limitations transforming NLOS problem into virtual Line-Of-Sight (LOS) one. Since information...

This paper presents the design of a non-invasive, non-contact remote pressure sensor using free-space optics, an electronically controlled variable focus lens (ECVFL), and standard liquid manometer to monitor inside high temperature chambers in harsh hazardous environments. The proposed does not require transparent manometers, cameras close proximity determine as level are monitored remotely. sensing mechanism is ideal for use toxic environments, such chemical plants well volatile...

A mathematical construct ‘Phasor Fields’ (P-Fields) is used to develop a light transport model for non-line-of-sight (NLOS) imaging applications. We show that NLOS can be treated as conventional line-of-sight (LOS) using P-Fields.

Gaussian beams are often used in optical systems. The fundamental TEM00 mode is the most common of modes present various devices, systems and equipment. Within an system, it that this beam passes through a circular aperture finite diameter. Such apertures include irises, spatial filters, Photo-Detectors (PDs) mounts with rims. magnitude power passing finite-sized well-documented for cases where center clear aperture, chopped off symmetrically all radial directions on given plane. More than...

Fluorescence lifetime imaging (FLIM) is used for measuring material properties in a wide range of applications, including biology, medical imaging, chemistry, and science. In frequency-domain FLIM (FD-FLIM), the object interest illuminated with temporally modulated light source. The fluorescence measured by computing correlations emitted demodulation function at sensor. signal-to-noise ratio (SNR) acquisition time FD-FLIM system determined coding scheme (modulation functions). this article,...

To the best of our knowledge, we propose first broadband variable fiber-optic attenuator (VFOA) using a digital micromirror device (DMD). The VFOA design is based on unique double reflection geometry structure that counters strong spectral attenuation inherent when implementing single-mode-fiber light coupling via pixelated blazed grating such as DMD. demonstrated features ~C-band 1530- to 1560-nm operation with plusmn0.17-dB in-band variation and 25-dB dynamic range. This high repeatability...

To the best of our knowledge, proposed for first time is design an optically broadband variable photonic delay line (VPDL) using electronically controlled focus lens (ECVFL), mirror motion, and beam-conditioned free-space laser beam propagation. This loss-minimized fiber-coupled VPDL micro-optic components has ability to simultaneously provide optical attenuation controls analog-mode high-resolution (subpicoseconds) continuous delays over a moderate (e.g., <5 ns) range delays. An example...

In this paper, we present analytical expressions for the coupling of fundamental Gaussian mode into a fiber collimator (FC) using two-lens system. For system, also derive limiting condition imposed on focal lengths two individual lenses and their mutual separation near-to-perfect FC. Variations in spatial profile beam may occur due to various reasons. These include controlled changes inside mode-division multiplexed systems, undesired variations beams that pass through turbulent media. The...

Optical interferometry-based techniques are ubiquitous in various measurement, imaging, calibration, metrological, and astronomical applications. Repeatability, simplicity, reliability of measurements have ensured that interferometry its forms remains popular-and fact continues to grow-in almost every branch measurement science. In this paper, we propose a novel actively-controlled optical interferometer the Twyman-Green configuration. The active beam control within is result using an...

In this paper, we present a novel design for tunable beam collimator. A variable collimator assists in achieving an adaptive size of output collimated beam. Alternatively, it can also provide adjustable divergence angle noncollimated output. Tunable collimators are highly desirable various applications testing, engineering, and measurements. Such devices useful providing illumination samples or targets microscopes emulating different target distances characterizing the performance camera...

Intelligent fiber-optic value-added modules (VAMs) are proposed using what we believe to be a novel spatially multiplexed processing technique implemented with both reconfigurable and nonreconfigurable predesigned pixels per impinging beam that enables desired optical power split states needed for realizing two state VAM. The preferred design uses broadband micromirrors such as ones fabricated via microelectromechanical systems technology. basic VAM micromirror pixels, where each pixel has...

We present an experimental demonstration of a Laguerre–Gauss (LG) spectrum measurement technique using variable focus lenses that is able to measure the strengths constituent modes in unknown incoming light beam with highest possible efficiency. The experiment modifies classical projective, phase flattening by including variable-sized pinhole and two-electronic-lens imaging system tuned for each mode give detection efficiency irrespective waist LG chosen projection/decomposition. modified...