Our simulation-based investigation of the TiN NHA/SiO2/Si stack's sensitivity in various conditions shows that substantial sensitivities are observed. The predicted maximum sensitivity is 2305 nm per refractive index unit (nm RIU⁻¹), occurring when the superstrate's refractive index matches that of the SiO2 layer. A detailed investigation into the combined effects of plasmonic and photonic resonances—including surface plasmon polaritons (SPPs), localized surface plasmon resonances (LSPRs), Rayleigh anomalies (RAs), and photonic microcavity modes (Fabry-Perot resonances)—is performed to understand their influence on this result. This study, by showcasing the tunable nature of TiN nanostructures for plasmonics, also anticipates the design of advanced sensing devices, operable in a broad range of conditions.

Concave hemispherical structures, laser-inscribed on optical fiber end-facets, serve as mirror substrates for tunable, open-access microcavities, as we demonstrate. Achieving finesse values of up to 200, performance is predominantly stable across all stability levels. Cavity operation, exceptionally near the stability limit, allows for attainment of a peak quality factor of 15104. Through a 23-meter narrow waist design, the cavity demonstrates a Purcell factor of 25, facilitating experiments requiring optimal lateral optical access or extensive separation of the mirrors. Rodent bioassays Laser-inscribed mirror profiles, offering tremendous variability in form and applicability to a broad spectrum of surfaces, unlocks significant potential for microcavity innovation.

Improvements in optical performance are projected to arise from laser beam figuring (LBF), a technological advancement in ultra-precise surface shaping. According to our understanding, we initially presented CO2 LBF achieving complete spatial frequency error convergence with insignificant stress levels. We found that material densification and melt-induced subsidence and surface smoothing, when kept within specific parameters, successfully limits both form error and roughness. In this regard, an innovative densification-melting effect is introduced to explicate the physical processes and furnish guidance for nano-level precision shaping, and the simulation results across diverse pulse durations conform well to the experimental results. In addition to suppressing laser scanning ripples (mid-spatial-frequency artifacts) and decreasing the size of the control data set, a clustered overlapping processing technique is proposed, treating the laser processing within each sub-region as a tool influence function. Through the combined influence of TIF's depth-figuring control, we conducted LBF experiments, leading to a reduction in the form error root mean square (RMS) from 0.009 to 0.003 (a change of 6328 nanometers), while leaving microscale roughness (0.447 nanometers to 0.453 nanometers) and nanoscale roughness (0.290 nanometers to 0.269 nanometers) intact. Optical manufacturing gains a new, high-precision, and low-cost method through the synergistic effects of densi-melting and clustered overlapping processing, exemplified by the LBF process.

Our research, for the first time according to our knowledge, details a multimode fiber laser with spatiotemporal mode-locking (STML), powered by a nonlinear amplifying loop mirror (NALM), that emits dissipative soliton resonance (DSR) pulses. Multimode interference filtering, along with NALM's influence within the cavity's complex filtering, makes the STML DSR pulse wavelength-tunable. In the same vein, diverse DSR pulse forms are produced, including multiple DSR pulses, and the period-doubling bifurcations of single DSR pulses and multiple DSR pulses. These findings offer further insight into the intricate nonlinear behavior of STML lasers, with the potential to inform the enhancement of multimode fiber laser performance.

We theoretically study the propagation of self-focusing vectorial Mathieu and Weber beams, originating from nonparaxial Mathieu and Weber accelerating beams, respectively. Paraboloids and ellipsoids facilitate automatic focusing, the focal fields displaying tightly focused characteristics reminiscent of a high NA lens. The relationship between beam characteristics and the focal spot size, as well as the energy proportion of the longitudinal component within the focal field, is demonstrated. A more superior focusing performance is demonstrated by a Mathieu tightly autofocusing beam, where the superoscillatory longitudinal field component can be amplified by altering the order and interfocal separation. These results are predicted to shed new light on autofocusing beam behavior and the high precision focusing of vector beams.

The technology of modulation format recognition (MFR) is central to adaptive optical systems, with applications in both commercial and civilian domains. Neural networks have facilitated the impressive success of the MFR algorithm, fueled by the rapid progress in deep learning. The high complexity of underwater channels significantly impacts the design of neural networks for improved MFR performance in UVLC. This often results in intricate architectures that are costly in computation and impede fast allocation and real-time processing. A lightweight and efficient reservoir computing (RC) approach is proposed in this paper, distinguished by trainable parameters constituting only 0.03% of those in typical neural network (NN)-based methods. For improved RC outcomes in MFR procedures, we propose robust algorithms for feature extraction, including coordinate transformations and folding algorithms. The proposed RC-based methods are applied to six modulation formats, which are: OOK, 4QAM, 8QAM-DIA, 8QAM-CIR, 16APSK, and 16QAM. The experimental results for our RC-based methods show exceptionally rapid training times, taking just a few seconds, and consistently high accuracy rates across various LED pin voltages; the majority of results exceeding 90% and a peak accuracy of nearly 100%. RC design considerations, focusing on achieving optimal performance by balancing accuracy and time expenditure, are explored, contributing to better MFR practices.

Employing a pair of inclined interleaved linear Fresnel lens arrays within a directional backlight unit, a novel autostereoscopic display was designed and its performance was evaluated. To ensure simultaneous presentation, differing high-resolution stereoscopic image pairs are delivered to each of the viewers using time-division quadruplexing. The horizontal range of the viewing zone is augmented by the inclination of the lens array, allowing two observers to have unique perspectives corresponding to their respective eye locations, avoiding any visual overlap between them. Therefore, two viewers, lacking specialized eyewear, can coexist within the same 3D space, allowing for interaction and collaboration by means of direct manipulation and the preservation of visual connection.

We posit, a novel assessment methodology, designed for evaluating the three-dimensional (3D) characteristics of an eye-box volume within a near-eye display (NED), using a single-distance light-field (LF) data acquisition. In contrast to the traditional method of eye-box evaluation, which employs a light-measuring device (LMD) that varies its position along both lateral and longitudinal dimensions, the presented approach leverages the luminance field of the light (LFLD) from near-eye data (NED) acquired at a single viewing distance, enabling a simple post-processing calculation of the 3D eye-box volume. Employing an LFLD representation, we examine the efficiency of 3D eye-box evaluation, results corroborated by Zemax OpticStudio simulations. Symbiotic organisms search algorithm For experimental confirmation of our augmented reality NED, we acquired an LFLD specifically at a single observation distance. Across the 20 mm distance range, the assessed LFLD successfully established a 3D eye-box, thus incorporating measurement conditions where direct light ray distribution assessment was problematic using conventional methodologies. Actual images of the NED, captured both inside and outside the assessed 3D eye-box, are used to further validate the proposed method.

This paper introduces a metasurface-modified leaky-Vivaldi antenna (LVAM). In the high-frequency operating band (HFOB), a Vivaldi antenna, incorporating a metasurface, achieves backward frequency beam scanning from -41 to 0 degrees, while maintaining aperture radiation in the low-frequency operating band (LFOB). Slow-wave transmission within the LFOB is accomplished by considering the metasurface as a transmission line. For fast-wave transmission within the HFOB, the metasurface can be modeled as a 2D periodic leaky-wave structure. LVAM's simulated performance reveals -10dB return loss bandwidths of 465% and 400%, and realized gain figures of 88-96 dBi and 118-152 dBi, encompassing the 5G Sub-6GHz (33-53GHz) band and the X band (80-120GHz), respectively. The test results are consistent with the anticipated simulated results. This innovative dual-band antenna, capable of simultaneously operating in both the 5G Sub-6GHz communication band and military radar band, will influence the future integration of communication and radar antenna systems.

Employing a straightforward two-mirror resonator, we report on a high-power HoY2O3 ceramic laser at 21 micrometers, presenting controllable output beam profiles, encompassing the LG01 donut, flat-top, and TEM00 modes. CAL101 A Tm fiber laser beam, in-band pumped at 1943nm and shaped by coupling optics—a capillary fiber and lens combination—induced distributed pump absorption in HoY2O3, selectively exciting the target mode. This resulted in 297 W LG01 donut, 280 W crater-like, 277 W flat-top, and 335 W TEM00 mode output, corresponding to absorbed pump powers of 535 W, 562 W, 573 W, and 582 W, respectively. The slope efficiencies were 585%, 543%, 538%, and 612% respectively. We posit that this is the first demonstration of laser generation with a continuously tunable output intensity profile, encompassing the 2-meter wavelength band.