Given this standard, the tradeoffs of each of the three designs, combined with the impact of crucial optical properties, can be quantified and compared, ultimately providing useful recommendations for selecting configurations and optical parameters in LF-PIV implementation.
The directional cosines of the optic axis hold no influence over the magnitudes of the direct reflection amplitudes, r_ss and r_pp. Despite – or -, the azimuthal angle of the optic axis remains unchanged. Both r_sp and r_ps, amplitudes associated with cross-polarization, demonstrate oddness; furthermore, they obey the fundamental relations r_sp(+) = r_ps(+) and r_sp(+) + r_ps(−) = 0. Complex reflection amplitudes are likewise governed by these symmetries, which apply to absorbing media with complex refractive indices. Near-normal incidence on a uniaxial crystal results in reflection amplitudes that can be expressed analytically. The angle of incidence's effect on reflection amplitudes for unchanged polarization (r_ss and r_pp) results in corrections that are second-order terms. The equal amplitudes of cross-reflection, r_sp and r_ps, prevail at normal incidence, with corrections to their values being first-order approximations with respect to the angle of incidence and possessing opposing signs. Non-absorbing calcite and absorbing selenium reflection examples are given, encompassing normal incidence and both small-angle (6 degrees) and large-angle (60 degrees) incidences.
Through the utilization of Mueller matrix polarization imaging, a novel biomedical optical imaging technique, both polarization and isotropic intensity images of the surface structures of biological tissue samples can be generated. A system for Mueller polarization imaging, in reflection mode, is presented in this paper to obtain the Mueller matrix from specimens. Diattenuation, phase retardation, and depolarization are extracted from the specimens using a conventional Mueller matrix polarization decomposition technique and a novel direct method. Substantiated by the results, the direct method is found to be more facile and rapid than the traditional decomposition approach. The polarization parameter combination approach is subsequently introduced, wherein any two of the diattenuation, retardation, and depolarization parameters are combined, enabling the definition of three novel quantitative parameters that serve to delineate intricate anisotropic structures more precisely. To showcase the efficacy of the introduced parameters, in vitro sample images are displayed.
Significant application potential resides in the intrinsic wavelength selectivity of diffractive optical elements. Our methodology hinges on fine-tuning wavelength selectivity, precisely managing the efficiency distribution across specific diffraction orders for wavelengths from ultraviolet to infrared, accomplished using interlaced, double-layer, single-relief blazed gratings composed of two materials. The dispersion characteristics of inorganic glasses, layer materials, polymers, nanocomposites, and high-index liquids are used to determine the impact of intersecting or partially overlapping dispersion curves on diffraction efficiency in multiple orders, offering guidance for the selection of materials based on the required optical performance. By manipulating the grating's depth and thoughtfully selecting materials, a wide assortment of small or large wavelength ranges can be assigned to differing diffraction orders with exceptional efficiency, rendering them suitable for wavelength-selective optical systems, including imaging and broadband lighting functions.
Prior methodologies for resolving the two-dimensional phase unwrapping problem (PHUP) often included discrete Fourier transforms (DFTs) and diverse techniques. Despite this, a formal approach to solving the continuous Poisson equation for the PHUP, leveraging continuous Fourier transforms and distribution theory, remains unreported, as far as we are aware. In general, the established solution to this equation is constructed by convolving a continuous Laplacian approximation with a unique Green function, the Fourier Transform of which is non-existent mathematically. Applying the Yukawa potential, a Green function with a defined Fourier spectrum, offers an alternative route to solving an approximated Poisson equation. This subsequently initiates the implementation of a standard Fourier transform-based unwrapping algorithm. In this work, the general procedure is articulated for this approach through the examination of some reconstructions using both synthetic and real data.
Using a limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) optimization technique, we generate phase-only computer-generated holograms for a 3D target with multiple depths. To achieve partial evaluation of the hologram during optimization, we introduce a novel method leveraging L-BFGS with sequential slicing (SS). This method only computes the loss function for a single slice of the 3D reconstruction in each iteration. Its curvature-recording capability enables L-BFGS to demonstrate robust imbalance suppression under the constraints of the SS technique.
We analyze the problem of how light behaves when encountering a two-dimensional arrangement of uniform spherical particles that are positioned inside a boundless, uniform, light-absorbing medium. The optical response of this system, including the effects of multiple light scattering, is characterized by equations derived through a statistical methodology. Numerical results for the spectral response of coherent transmission, reflection, incoherent scattering, and absorption coefficients are provided for thin films of dielectrics, semiconductors, and metals that incorporate a monolayer of particles with different spatial configurations. Sodium L-ascorbyl-2-phosphate chemical A comparison is drawn between the characteristics of the inverse structure particles, consisting of the host medium material, and the results, and the opposite is also true. A correlation between the monolayer filling factor and the redshift of surface plasmon resonance in gold (Au) nanoparticles within a fullerene (C60) matrix is presented in the accompanying data. Their qualitative agreement aligns with the established experimental findings. The development of novel electro-optical and photonic devices may benefit from these findings.
A detailed derivation of the generalized laws of reflection and refraction, originating from Fermat's principle, is given for a metasurface geometry. Initially, we use the Euler-Lagrange equations to analyze the path taken by a light ray while propagating across the metasurface. The analytical derivation of the ray-path equation is corroborated by numerical simulations. Generalized laws of refraction and reflection, applicable in both gradient-index and geometrical optics, exhibit three key characteristics: (i) Multiple reflections within the metasurface generate a collection of emergent rays; (ii) These laws, while grounded in Fermat's principle, contrast with prior findings; (iii) Their applicability extends to gradient-index and geometrical optics.
In our design, a two-dimensional freeform reflector is combined with a scattering surface modeled via microfacets, which represent the small, specular surfaces inherent in surface roughness. From the model, a convolution integral was derived from the scattered light intensity distribution, leading to an inverse specular problem after deconvolution. Therefore, the configuration of a reflector possessing a scattering surface can be determined by deconvolution, followed by the resolution of the standard inverse problem in specular reflector design. We observed a few percentage variation in reflector radius due to surface scattering, with the degree of variation directly proportional to the amount of scattering.
Analyzing the optical reaction of two multilayer systems, showcasing one or two corrugated interfaces, we draw upon the microstructures seen in the wing scales of the Dione vanillae butterfly. The C-method is employed to calculate reflectance, which is then compared to the reflectance of a planar multilayer. Each geometric parameter's influence is thoroughly investigated, and the angular response, essential for iridescent structures, is examined. The purpose of this study is to furnish insights that support the design of multilayer structures, demonstrating controlled optical behaviors.
We introduce a method for real-time phase-shifting interferometry in this paper. A parallel-aligned liquid crystal, implemented on a silicon display, functions as a customized reference mirror for this technique. Macropixels are programmed onto the display in preparation for the four-step algorithm, subsequently partitioned into four sections with specific phase adjustments applied to each. Sodium L-ascorbyl-2-phosphate chemical Spatial multiplexing permits the extraction of wavefront phase information at a rate directly constrained by the detector's integration time. The customized mirror's function encompasses both compensating the initial curvature of the object being studied and introducing the indispensable phase shifts for phase calculation. Exemplified are the reconstructions of static and dynamic objects.
In a prior work, a modal spectral element method (SEM), notable for its hierarchical basis built from modified Legendre polynomials, was shown to be remarkably effective in the analysis of lamellar gratings. This work, retaining the identical ingredients, extends its methodology to the general situation of binary crossed gratings. Demonstrating the SEM's geometric prowess are gratings whose patterns are not coordinated with the elementary cell's limits. The method's accuracy is confirmed through comparison to the Fourier modal method (FMM) for anisotropic crossed gratings, and to the FMM with adaptive spatial resolution when evaluating a square-hole array in a silver film.
An investigation into the optical force acting on a nano-dielectric sphere, illuminated by a pulsed Laguerre-Gaussian beam, was undertaken theoretically. Under the assumption of dipole approximation, analytical expressions for optical forces were mathematically derived. From the provided analytical expressions, the effects of pulse duration and beam mode order (l,p) on the optical force were thoroughly investigated.