One can evaluate zonal power and astigmatism without the need for ray tracing, considering the composite contributions from the F-GRIN and freeform surfaces. A commercial design software numerical raytrace evaluation is used to compare the theory. Comparing the results, it's evident that the raytrace-free (RTF) calculation models all raytrace contributions within a tolerable margin of error. An example highlights the ability of linear index and surface terms in an F-GRIN corrector to rectify the astigmatism of a tilted spherical mirror. The RTF calculation, taking into account the spherical mirror's influence, determines the astigmatism correction required by the optimized F-GRIN corrector.
To categorize copper concentrates pertinent to the copper refining process, a study employing reflectance hyperspectral imaging in visible and near-infrared (VIS-NIR) (400-1000 nm) and short-wave infrared (SWIR) (900-1700 nm) bands was conducted. see more A quantitative mineral evaluation, alongside scanning electron microscopy, was applied to characterize the mineralogical composition of 82 copper concentrate samples that were pressed into pellets with a diameter of 13 millimeters. Bornite, chalcopyrite, covelline, enargite, and pyrite are exemplified in these pellets as the most representative minerals. For training classification models, a collection of average reflectance spectra is gathered from 99-pixel neighborhoods in each pellet hyperspectral image within the VIS-NIR, SWIR, and VIS-NIR-SWIR databases. Among the classification models examined in this work are a linear discriminant classifier, a quadratic discriminant classifier, and a fine K-nearest neighbor classifier (FKNNC), each possessing unique properties. Employing both VIS-NIR and SWIR bands, as indicated by the results, allows for precise classification of similar copper concentrates, which differ only minimally in their mineralogical components. The FKNNC classification model, of the three tested, exhibited superior performance in terms of overall classification accuracy. Applying VIS-NIR data alone resulted in a 934% accuracy rate on the test set. When solely using SWIR data, the accuracy was 805%. Integrating both VIS-NIR and SWIR bands produced the most accurate results, with an accuracy of 976% on the test data.
This paper examines the application of polarized-depolarized Rayleigh scattering (PDRS) for simultaneously determining mixture fraction and temperature in non-reacting gas mixtures. Past implementations of this approach have been advantageous in the realm of combustion and reacting flow applications. This study sought to increase the applicability of the approach to non-isothermal mixing processes involving varied gases. The versatility of PDRS is evident in its potential for applications outside combustion, specifically in aerodynamic cooling and turbulent heat transfer investigations. A proof-of-concept experiment, utilizing gas jet mixing, details the general procedure and requirements for applying this diagnostic. A numerical sensitivity analysis is subsequently detailed, offering a comprehension of the technique's applicability with varied gas mixtures and the anticipated measurement error. From this gaseous mixture diagnostic, this study showcases the acquisition of appreciable signal-to-noise ratios, allowing for the simultaneous visualization of both temperature and mixture fraction, even with less-than-ideal optical properties of the mixing species.
A high-index dielectric nanosphere provides an effective mechanism for enhancing light absorption by exciting a nonradiating anapole. This study delves into the effect of localized lossy defects on nanoparticles, using Mie scattering and multipole expansion techniques, revealing a low susceptibility to absorption. The scattering intensity's responsiveness is dependent on the nanosphere's defect distribution. Nanospheres possessing a high refractive index and uniform loss experience a significant and rapid reduction in the scattering attributes of each resonant mode. Loss strategically placed within the strong-field zones of the nanosphere enables independent control over other resonant modes, ensuring the anapole mode remains intact. The escalation of losses results in opposing trends for the electromagnetic scattering coefficients of anapole and other resonant modes, accompanied by a substantial decrease in corresponding multipole scattering. see more Electric field intensities impacting regions are a primary factor in susceptibility to losses; however, the anapole's dark mode characteristic, inhibiting light emission and absorption, renders it stubbornly resistant to change. Our investigation reveals new design strategies for multi-wavelength scattering regulation nanophotonic devices, which stem from local loss manipulation of dielectric nanoparticles.
Wavelength-dependent Mueller matrix imaging polarimeters (MMIPs) have proven their value beyond 400 nanometers in diverse sectors, however, the ultraviolet (UV) spectrum awaits significant instrumentation and application breakthroughs. Our research has led to the development of a UV-MMIP, to the best of our understanding the first of its kind, achieving high resolution, sensitivity, and accuracy at the 265-nanometer wavelength. A novel polarization state analyzer, modified for stray light reduction, is employed to generate high-quality polarization images, and the measured Mueller matrix errors are calibrated to a sub-0.0007 level at the pixel scale. The measurements of unstained cervical intraepithelial neoplasia (CIN) specimens showcase the superior performance of the UV-MMIP. Depolarization images from the UV-MMIP show a marked improvement in contrast over the 650 nm VIS-MMIP results. Using the UV-MMIP technique, an evolutionary pattern of depolarization is readily apparent in specimens of normal cervical epithelium, CIN-I, CIN-II, and CIN-III, which can result in a maximum 20-fold elevation in depolarization. The observed evolution could prove instrumental in defining CIN stages, although the VIS-MMIP struggles to provide a clear distinction. By exhibiting higher sensitivity, the UV-MMIP proves itself a valuable tool for use in polarimetric applications, as the results confirm.
Realizing all-optical signal processing necessitates the use of all-optical logic devices. The full-adder is the fundamental building block in an arithmetic logic unit, critical to all-optical signal processing systems. The photonic crystal serves as the foundation for the design of an ultrafast and compact all-optical full-adder, as detailed in this paper. see more Within this framework, three waveguides are each linked to a primary input. To foster symmetry and boost the device's operational efficiency, we have introduced a new input waveguide. A linear point defect and two nonlinear rods of doped glass and chalcogenide are utilized to achieve specific light behavior. The square cell's construction is based upon 2121 dielectric rods, each possessing a 114 nm radius, and a 5433 nm lattice constant. The proposed structure's area is 130 square meters, and its maximum delay is approximately 1 picosecond, implying a minimum data rate of 1 terahertz. The normalized power in low states is at its maximum, 25%, whereas the normalized power in high states is at its minimum, 75%. Because of these characteristics, the proposed full-adder is suitable for high-speed data processing systems.
We introduce a machine learning framework for grating waveguide engineering and augmented reality applications, achieving considerable speed improvements compared to finite element-based numerical methods. To design slanted, coated, interlayer, twin-pillar, U-shaped, and hybrid structure gratings, we explore structural elements like grating slanted angle, depth, duty cycle, coating ratio, and interlayer thickness. The dataset, containing samples ranging from 3000 to 14000, was processed with a multi-layer perceptron algorithm, constructed using the Keras framework. More than 999% coefficient of determination and an average absolute percentage error between 0.5% and 2% were observed in the training accuracy. Our hybrid grating structure, built in parallel, achieved a diffraction efficiency of 94.21% and a uniformity of 93.99% simultaneously. Regarding tolerance analysis, this hybrid structure grating performed exceptionally well. This paper's high-efficiency artificial intelligence waveguide methodology leads to the optimal design of a grating waveguide structure. Artificial intelligence-driven optical design benefits from theoretical guidance and technical reference.
A stretchable substrate dynamical focusing cylindrical metalens, comprising a double-layer metal structure, was designed to operate at 0.1 THz, according to impedance-matching theory. In terms of dimensions, the metalens exhibited a diameter of 80 mm, an initial focal length of 40 mm, and a numerical aperture of 0.7. Changing the size of the metal bars within the unit cell structures enables the control of the transmission phase, which can span the range of 0 to 2; this is followed by the spatial arrangement of the various unit cells to achieve the designed phase profile of the metalens. The substrate's stretching range, encompassing 100% to 140%, brought about a shift in focal length from 393mm to 855mm, significantly increasing the dynamic focusing range to 1176% of the smallest focal length, yet simultaneously decreasing the focusing efficiency to 279% from 492%. The computational model successfully produced a dynamically adjustable bifocal metalens, structured through the reorganization of its unit cells. Given the same stretching ratio, a bifocal metalens displays a broader focal length control range compared to a single focus metalens.
Future endeavors in millimeter and submillimeter observations concentrate on meticulously charting the intricate origins of the universe, as revealed through the cosmic microwave background's subtle imprints. To accomplish this multichromatic sky mapping, large and sensitive detector arrays are imperative. Currently, the coupling of light to such detectors is being examined through multiple avenues, including coherently summed hierarchical arrays, platelet horns, and antenna-coupled planar lenslets.