This technique paves the way for producing financially accessible, extremely large primary mirrors intended for space-based telescopes. Due to the pliant nature of the membrane material, this mirror is conveniently storable in a rolled-up configuration within the launch vehicle, and is then deployed once in space.

Reflective optical systems, while theoretically capable of producing ideal optical designs, often prove less practical than their refractive counterparts because of the inherent difficulties in achieving high accuracy of the wavefront. Mechanically joining cordierite optical and structural components, a ceramic material with a notably low thermal expansion coefficient, offers a promising approach towards constructing reflective optical systems. Measurements using interferometry on a prototype product revealed diffraction-limited performance within the visible spectrum, a characteristic that persisted even after the sample was cooled to 80 Kelvin. For the application of reflective optical systems, especially in cryogenic environments, this new technique might be the most economical option.

Promising prospects for perfect absorption and angular selectivity in transmission are associated with the Brewster effect, a notable physical law. Previous research has thoroughly examined the Brewster effect in isotropic materials. Although this is the case, research dedicated to anisotropic substances has been conducted with limited scope. A theoretical examination of the Brewster effect in quartz crystals with tilted optical axes is conducted in this work. We derive the criteria for the Brewster effect to arise within anisotropic material structures. check details Crystal quartz's Brewster angle was effectively managed by altering the orientation of its optical axis, as the numerical findings definitively reveal. An investigation into the reflection of crystal quartz, specifically its dependence on wavenumber, incidence angle, and tilt angle, is undertaken. Furthermore, we explore the influence of the hyperbolic region on the Brewster effect exhibited by quartz crystals. check details At a wavenumber of 460 cm⁻¹ (Type-II), there is an inverse correlation between the Brewster angle and the tilted angle. Unlike other cases, a wavenumber of 540 cm⁻¹ (Type-I) reveals a positive relationship between the Brewster angle and the tilted angle. An investigation into the correlation between the Brewster angle and wavenumber across various tilted angles concludes this exploration. This work's contributions to crystal quartz research will be substantial, potentially initiating the development of tunable Brewster devices employing anisotropic materials.

Analysis of transmittance increase in the Larruquert group's investigation led to the initial inference of pinholes in the A l/M g F 2 material. Although dark-field and bright-field transmission microscopy had previously identified pinholes in A l/M g F 2 over the past 80 years, no direct evidence of their presence was presented. Small in size, they occupied the space between several hundred nanometers and several micrometers. The pinhole's non-real status, in part, was predicated on the lack of the Al element. Adding more Al material does not diminish the dimensions of the pinholes. The formation of pinholes was governed by the aluminum film's deposition rate and the substrate's heating temperature, being uninfluenced by the choice of substrate material. This research eliminates a previously unacknowledged scattering source, thereby facilitating advancements in ultra-precise optical systems, such as mirrors for gyro-lasers, enabling gravitational wave detection, and advancing coronagraphic technology.

Passive phase demodulation's spectral compression method yields a potent approach for attaining a high-powered, single-frequency second-harmonic laser. By utilizing (0,) binary phase modulation, a single-frequency laser's spectrum is broadened to mitigate stimulated Brillouin scattering in a high-power fiber amplifier, and the output is compressed to a single frequency via frequency doubling. The phase modulation system's performance, including modulation depth, frequency response characteristics of the modulation system, and modulation signal noise, ultimately determines the efficacy of the compression process. A numerical model is designed to simulate the effect of these factors on the spectral characteristics of SH. The experimental observation of a compression rate reduction at high-frequency phase modulation, accompanied by spectral sidebands and a pedestal, is mirrored by the simulation results.

A novel approach to optically directing nanoparticles using a photothermal trap powered by a laser is presented, and the mechanisms by which external factors modify the trap's characteristics are explained. The primary cause of gold nanoparticle directional motion, as revealed through optical manipulation experiments and finite element simulations, stems from the drag force. The laser power applied to the substrate, combined with its boundary temperature and thermal conductivity at the bottom, and the liquid level in the solution, ultimately impact the intensity of the laser photothermal trap and thus, the directional movement and deposition speed of gold particles. The results illuminate the origin of the laser photothermal trap and the gold particles' three-dimensional spatial velocity configuration. It additionally specifies the height at which photothermal effect initiation occurs, thus illustrating the differentiation between the influence of light force and the photothermal effect. This theoretical study enables the successful manipulation of nanoplastics. Photothermal-driven movement of gold nanoparticles is investigated deeply in this study, using both experimental and computational approaches. This in-depth analysis is crucial to advancing the theoretical understanding of optical nanoparticle manipulation utilizing photothermal effects.

Within a multilayered three-dimensional (3D) structure, the moire effect was observed, with voxels positioned at the points of a simple cubic lattice array. Visual corridors manifest due to the presence of the moire effect. Distinct angles, with rational tangents, are characteristic of the frontal camera's corridor appearances. Our research delved into the consequences of variations in distance, size, and thickness. Physical experiments, corroborated by computer simulations, revealed the unique angles of the moiré patterns for the three camera positions situated near the facet, edge, and vertex. A set of rules governing the conditions necessary for observing moire patterns in a cubic lattice arrangement was determined. Crystallography and the minimization of moiré effects in LED-based three-dimensional volumetric displays can both utilize these findings.

The spatial resolution of laboratory nano-computed tomography (nano-CT) can reach up to 100 nanometers, making it a popular technique owing to its volume-based benefits. Still, the wandering of the x-ray source's focal spot and the thermal growth of the mechanical components may cause a drift in the projection throughout extended scanning periods. Severe drift artifacts mar the three-dimensional reconstruction generated from the shifted projections, compromising the spatial resolution of the nano-CT. Sparse, rapidly-acquired projections, while a common drift correction technique, face challenges in nano-CT due to high noise and significant projection contrast variations, hindering the effectiveness of existing correction methods. A novel approach to projection registration, starting with an initial estimate and evolving to a precise alignment, utilizes characteristics from both the gray-scale and frequency spaces of the projections. According to simulation data, the proposed method exhibits a 5% and 16% increased precision in drift estimation compared to the prominent random sample consensus and locality-preserving matching methods rooted in feature-based algorithms. check details A significant upgrade in nano-CT imaging quality is facilitated by the suggested method.

This paper proposes a design for a high extinction ratio Mach-Zehnder optical modulator. Destructive interference between waves in the Mach-Zehnder interferometer (MZI) arms is achieved using the germanium-antimony-selenium-tellurium (GSST) phase change material's tunable refractive index, leading to amplitude modulation. The MZI benefits from a novel asymmetric input splitter, engineered to offset the undesirable amplitude variations between its arms, thereby boosting the performance of the modulator. Three-dimensional finite-difference time-domain simulations of the designed modulator at 1550 nm reveal a remarkable extinction ratio (ER) of 45 and a low insertion loss (IL) of just 2 dB. The energy range (ER) demonstrates a level above 22 dB, and the intensity level (IL) stays below 35 dB, specifically in the 1500-1600 nm wavelength spectrum. By means of the finite-element method, the thermal excitation of GSST is modeled, subsequently providing estimates of the modulator's speed and energy consumption.

A strategy for minimizing the mid-to-high frequency errors in small aspheric molds of optical tungsten carbide is proposed, focusing on a rapid selection of critical process parameters through simulations of residual error after convolution with the tool influence function (TIF). By the end of the TIF's 1047-minute polishing procedure, the simulation optimizations for RMS and Ra, achieved convergence at 93 nm and 5347 nm, respectively. Compared to ordinary TIF, their convergence rates respectively achieved gains of 40% and 79%. Subsequently, a more refined and expeditious multi-tool combination smoothing suppression method is presented, along with the development of the associated polishing tools. With the use of a disc-shaped polishing tool boasting a fine microstructure, the global Ra of the aspheric surface decreased from 59 nm to 45 nm following a 55-minute smoothing process, upholding an exceptional low-frequency error (PV 00781 m).

To quickly determine the quality characteristics of corn, the potential of combining near-infrared spectroscopy (NIRS) with chemometrics was analyzed to detect the amount of moisture, oil, protein, and starch within the corn.