Upon completion of the phase unwrapping stage, the relative error of linear retardance is limited to 3%, and the absolute error of birefringence orientation is around 6 degrees. Initial observations show that polarization phase wrapping arises in thick samples or those with noticeable birefringence, leading to a subsequent Monte Carlo analysis of its influence on anisotropy parameters. Experiments are carried out on porous alumina with diverse thicknesses and multilayer tapes, in order to ascertain the viability of phase unwrapping using a dual-wavelength Mueller matrix system. Lastly, contrasting the temporal patterns of linear retardance during tissue dehydration before and after phase unwrapping underscores the necessity of the dual-wavelength Mueller matrix imaging system. This system is not only useful for evaluating anisotropy in static samples, but also for characterizing the patterns of polarization changes in dynamic samples.
Recently, the dynamic manipulation of magnetization using brief laser pulses has become a subject of significant interest. Through the application of second-harmonic generation and the time-resolved magneto-optical effect, a study of the transient magnetization at the metallic magnetic interface was undertaken. However, the ultrafast light-manipulated magneto-optical nonlinearity present in ferromagnetic composite structures for terahertz (THz) radiation is presently unclear. We demonstrate THz generation from a metallic heterostructure, Pt/CoFeB/Ta, attributable to a 6-8% contribution from magnetization-induced optical rectification and a 94-92% contribution from the combined effects of spin-to-charge current conversion and ultrafast demagnetization. THz-emission spectroscopy is revealed by our results to be a potent method for analyzing the nonlinear magneto-optical effect in ferromagnetic heterostructures within a picosecond timeframe.
The highly competitive waveguide display solution for augmented reality (AR) has generated a substantial amount of interest. A polarization-dynamic binocular waveguide display, using polarization volume lenses (PVLs) at the input stage and polarization volume gratings (PVGs) at the output stage, is put forward. Light from a singular image source, based on its polarization, is sent separately to the left and right eyes. PVLs' inherent deflection and collimation functionalities render unnecessary the inclusion of a dedicated collimation system, when contrasted with traditional waveguide displays. By capitalizing on the high effectiveness, broad angular range, and polarization selectivity of liquid crystal components, distinct images are precisely and independently created for each eye through manipulation of the image source's polarization. Through the proposed design, a compact and lightweight binocular AR near-eye display is established.
Recent observations indicate the formation of ultraviolet harmonic vortices within a micro-scale waveguide subjected to a high-power circularly-polarized laser pulse. Still, harmonic generation typically tapers off after a few tens of microns of propagation, because of the accumulating electrostatic potential, which diminishes the surface wave's vigor. To resolve this challenge, we posit the use of a hollow-cone channel. In a conical target setup, the laser intensity at the entrance is kept relatively low to minimize electron extraction, while the slow, focused nature of the conical channel counteracts the existing electrostatic field, permitting the surface wave to sustain a considerable amplitude over a significantly expanded distance. According to three-dimensional particle-in-cell modeling, harmonic vortices can be generated at a very high efficiency exceeding 20%. By the proposed methodology, powerful optical vortex sources are made possible within the extreme ultraviolet range, an area brimming with potential for both fundamental and applied physics research.
A novel line-scanning microscope for high-speed fluorescence lifetime imaging microscopy (FLIM) employing time-correlated single-photon counting (TCSPC) is presented in this report. A 10248-SPAD-based line-imaging CMOS, with a 2378m pixel pitch and a 4931% fill factor, and a laser-line focus optically conjugated to it, collectively form the system. Acquisition rates on our new line-sensor, enhanced with on-chip histogramming, are 33 times faster compared to our previously published results for bespoke high-speed FLIM platforms. We showcase the imaging potential of the high-speed FLIM platform across a spectrum of biological applications.
Investigating the generation of strong harmonics, sum and difference frequencies through the propagation of three pulses with differing wavelengths and polarizations in Ag, Au, Pb, B, and C plasmas. ZX703 order The results of this investigation confirm that difference frequency mixing is more efficient than sum frequency mixing. Under ideal laser-plasma interaction conditions, the sum and difference component intensities closely approximate those of the surrounding harmonics, which are significantly influenced by the 806nm pump laser.
Gas absorption spectroscopy, high-precision, is seeing increasing demand in both fundamental research and industrial applications like gas tracking and leak warnings. In this letter, a new, high-precision, real-time gas detection technique is proposed, as far as we can ascertain. A femtosecond optical frequency comb serves as the light source, leading to the creation of an oscillation frequency broadening pulse after the light's passage through a dispersive element and a Mach-Zehnder interferometer. In a single pulse duration, the four absorption lines from H13C14N gas cells are measured across five differing concentrations. The simultaneous attainment of a 5 nanosecond scan detection time and a 0.00055 nanometer coherence averaging accuracy is noteworthy. ZX703 order High-precision and ultrafast detection of the gas absorption spectrum is performed, successfully addressing the complexities associated with current acquisition systems and light sources.
This communication details a new, as per our understanding, class of accelerating surface plasmonic waves, the Olver plasmon. Surface waves traversing the silver-air interface are found to follow self-bending trajectories, classified in different orders, with the Airy plasmon considered the zeroth-order example. We present a plasmonic autofocusing hotspot arising from the interplay of Olver plasmons, with the focusing characteristics subject to control. The creation of this unique surface plasmon is proposed, verified through numerical simulations employing the finite-difference time-domain method.
In high-speed and long-distance visible light communication, we employed a newly fabricated 33 violet series-biased micro-LED array, distinguished by its high optical power output. Orthogonal frequency division multiplexing modulation, distance-adaptive pre-equalization, and a bit-loading algorithm allowed the achievement of data rates of 1023 Gbps, 1010 Gbps, and 951 Gbps at distances of 0.2 meters, 1 meter, and 10 meters, respectively, falling short of the 3810-3 forward error correction limit. In our judgment, these violet micro-LEDs have established the highest data rates in free space, and this also represents the first demonstration of communication exceeding 95 Gbps over a 10-meter span using micro-LEDs.
Modal decomposition methods are applied to separate and recover the modal content in a multimode optical fiber. Regarding mode decomposition experiments in few-mode fibers, we analyze the appropriateness of the commonly used similarity metrics in this letter. Experimental results highlight the misleading nature of the conventional Pearson correlation coefficient, underscoring its inadequacy as the sole metric for decomposition performance. Regarding the correlation, we examine multiple options and present a new metric that best quantifies the difference in complex mode coefficients, established from received and recovered beam speckles. We also show that this metric enables the transfer of knowledge from pre-trained deep neural networks to experimental data, resulting in a demonstrably better performance.
Employing a Doppler frequency shift vortex beam interferometer, the dynamic and non-uniform phase shift is retrieved from the petal-like fringes formed by the coaxial superposition of high-order conjugated Laguerre-Gaussian modes. ZX703 order While uniform phase shifts produce a coherent rotation of petal-shaped fringes, the dynamic non-uniform phase shifts cause fringes at different radial distances to rotate at varying angles, consequently creating highly twisted and elongated petals. This poses difficulties in accurately identifying rotation angles and retrieving the phase through image morphology. A carrier frequency is introduced, without any phase shift, by using a rotating chopper, a collecting lens, and a point photodetector at the exit of the vortex interferometer, thereby addressing the problem. The non-uniform phase shift causes a divergence in Doppler frequency shifts across petals with varying radii, each owing to their unique rotation velocity. The implication of spectral peaks near the carrier frequency is the immediate determination of petal rotation velocities and the corresponding phase shifts at these radii. The surface deformation velocities of 1, 05, and 02 m/s had an observed relative error in the phase shift measurement that fell below a maximum of 22%. This method possesses the capability of exploiting mechanical and thermophysical dynamics, specifically from the nanometer to micrometer size range.
In the realm of mathematics, the operational characterization of any function can be mirrored by that of another function. Implementing this concept within an optical system yields structured light. An optical field distribution embodies a mathematical function within the optical system, and a diverse array of structured light fields can be generated via diverse optical analog computations applied to any input optical field. The Pancharatnam-Berry phase underpins the broadband performance of optical analog computing, a notably beneficial characteristic.