The spatiotemporal optical vortex (STOV) is unique, owing to its phase singularity in the space–time domain, and it can carry transverse orbital angular momentum (OAM). Diffraction a fundamental wave phenomenon that well known for conventional light; however, studies on diffraction of light with OAM are limited. Furthermore, methods enable fast detection STOVs lacking. Here, we theoretically experimentally study behaviors STOVs, which different from those light. patterns STOV pulses...

In this study, a nano-displacement measurement system is proposed and demonstrated both theoretically experimentally, which was based on modified Mach-Zehnder (M-Z) interferometer using two conjugated orbital angular momentum (OAM) beams. contrast to the previous M-Z-based OAM interferometer, reflection module inserted into reference arm instead of simple mirror. As result, effect transverse position-dependence phase-shift caused by dove prism can be clearly eliminated stable robust...

Orbital-angular-momentum (OAM) beams-based interferometers have recently been attracted significant interest and found various applications in the field of optical precision measurement. Whereas all-fiber OAM featured with superior characteristics compact size, low cost, extremely-low insertion-loss, inherent compatibility other fiber devices, less studied especially demonstrated experiment. In this study, we proposed experimentally an interferometer, where two conjugated beams generated by...

The structured light method is an effective non-contact measurement approach. calibration greatly affects the precision of systems. To construct a large-scale system with high accuracy, and precise gauge always required, which leads to increased cost. this end, in paper, planar mirror proposed reduce size An out-of-focus camera also overcome defocusing problem caused by shortened distance during procedure. experimental results verify accuracy method.

Many ultrafast phenomena in biology and physics are fundamental to our scientific understanding but have not yet been visualized owing the extreme speed sensitivity requirements imaging modalities. Two examples propagation of passive current flows through myelinated axons electromagnetic pulses dielectrics, which both key information processing living organisms electronic devices. Here, we demonstrate differentially enhanced compressed photography (Diff-CUP) directly visualize propagations...

Quantitative differential phase contrast (qDPC) microscopy can achieve imaging of unlabeled cell samples with high spatial resolution. However, qDPC is easily affected by the noise generated in experiments. In this manuscript, L0-norm regularization was introduced into reconstruction for sparse (L0-qDPC), including quantitative target and samples. After detailed comparison fidelity, contrast, resolution, convergence rate, L0-qDPC method provide a stable without parameter adjustment due to...

In fringe projection profilometry, the relationship between phase and height is of utmost significance to perform accurate measurement. To enhance accuracy robustness, a calibration method presented based on pattern geometric constraints. By analyzing distribution in image coordinate, this establishes one-to-one mapping directly, lens distortion camera considered involved mathematical description, so as eliminate error propagation. The (x, y) coordinates are calculated from with known...

The camera is the main sensor of vison-based human activity recognition, and its high-precision calibration distortion an important prerequisite task. Current studies have shown that multi-parameter model methods achieve higher accuracy than traditional in process calibration. However, these need hundreds or even thousands images to optimize model, which limits their practical use. Here, we propose a novel point-to-point method requires only dozens get dense rectification map. We designed...

A high-speed scanning stroboscopic fringe-pattern projection system is designed. rotating polygon mirror and a line-structured laser cooperate to produce stable unambiguous fringe patterns. The combines the rapidity of grating with high accuracy light source. patterns have fast frame rate, great density, precision, brightness, convenience in adjusting frequency, linewidth, amount phase shift. characteristics stability this are verified by experiments. Experimental results show that finest...

A stably acquiring and accurately demodulating interferogram is crucial for the interferometer to achieve ultra-high precision sensitivity measurements. In this study, a robust orbital angular momentum (OAM) beams-based Fizeau proposed experimentally demonstrated, which more compact stable than OAM interferometers with other structures due common optical path characteristic. accordance such an interferometric scheme, phase-demodulation method operated in domain of complex spectrum also...

Lasers are widely applied in assisted reproductive technologies, including sperm fixation, selection and intracytoplasmic injections, to reduce procedure time improve consistency reproducibility. However, quantitative studies on laser-induced photodamage of lacking. In this study, we demonstrated that, by using optical tweezers, the kinematic parameters freely swimming correlated with frequency as well percentage pausing duration longitudinal rolling same head trap. Furthermore, trapping...

Phase unwrapping is widely used in interferometry. In the typical least square (LS) method, noise wrapped phase cannot be removed. An improved algorithm based on total variation (TV) imposes L1-norm image gradient to improve sparsity. However, it may lead over-sparsity, and unwrapped will compressed if penalty term overlarge. this study, we proposed a sparse prior (SPUP) solve of interferograms diffraction microscopy (DPM). Since DPM has unique sample sparsity imaging field high-power...

A new iterative algorithm to be used precisely reconstruct near-field distribution from an interferogram of a laser output generated by cyclic radial-shearing interferometer is proposed. First, use window function around the zero-frequency part Fourier transform and calculation inverse part, we obtain background intensity interferogram. Then, according algorithm, reconstructed obtained in first step. numerical simulation actual experiment reconstruction with arbitrary amplitude are...

An analytic formula for the light field amplitude (and therefore also intensity) behind a circular aperture illuminated by spherical or plane waves in Fresnel limit is given, and essential difference between diffraction Fraunhofer discussed.

Cancellous bone is a widespread structure in creatural body, for instance, the femoral head and spondyle. The damage evolution crack growth of cattle cancellous were studied under three-point-bending load conditions. A series speckle images with deformation information surrounding tip recorded, full-field displacement distributions obtained at different loading levels by means digital correlation method (DSCM). Characterizations fracture analyzed. These results provide some useful studying...

For the existing monocular vision methods of pose (or position and orientation) measurement based on Perspective-n-Point problem, camera calibrations image corrections are complicated difficult due to lens distortion. Additionally, as their theoretical models, pinhole imaging model collinear equation only offer an ideal approximation for process area array camera. Thus, possesses inevitable systematic errors. To avoid these problems, a new measuring method is proposed, which replaces its...

On-line phase measuring profilometry (OPMP) for a rotating object is proposed. N frames of circular sinusoidal grating patterns are designed in advance, which the transmittance along radial direction and there fixed shifting pitch 2π/N between every adjacent two direction. While measured rotating, projected onto by digital light processing corresponding deformed caused at different positions captured charge coupled device camera. By pixel matching rotation transformation with special marks,...

This paper aims to develop a 3D panoramic sensor with catadioptric imaging system. First, the fringe pattern is designed in polar coordinate system match dimensions of hyperbolic mirror. Second, variable-frequency proposed obtain constant-frequency reconstruction real space. Experiments are conducted verify accuracy and feasibility, experimental results show effectiveness sensor.