A quantitative analysis model combining backward interval partial least squares (BiPLS), principal component analysis (PCA), and extreme learning machine (ELM) was developed, leveraging the BiPLS methodology in conjunction with PCA and ELM. The process of selecting characteristic spectral intervals was performed by BiPLS. The prediction residual error sum of squares, a critical metric obtained from Monte Carlo cross-validation, dictated the selection of the best principal components. Moreover, a genetic simulated annealing algorithm was used to optimize the parameters within the ELM regression model. Regression models for corn components (moisture, oil, protein, and starch) achieve satisfactory prediction, evidenced by determination coefficients (0.996, 0.990, 0.974, and 0.976), root mean square errors (0.018, 0.016, 0.067, and 0.109), and residual prediction deviations (15704, 9741, 6330, and 6236) respectively, thus meeting the demand for component detection. Through the selection of characteristic spectral intervals, the dimensionality reduction of spectral data, and nonlinear modeling, the NIRS rapid detection model shows increased robustness and accuracy in swiftly detecting multiple components in corn, offering an alternate strategy for rapid identification.
The methodology for measuring and validating steam dryness fraction in wet steam, based on dual-wavelength absorption, is explored in this paper. Fabricated for precise water vapor measurements at different pressures (1-10 bars), a thermally insulated steam cell, featuring a temperature-controlled window capable of withstanding up to 200°C, was designed to avoid condensation. Water vapor measurement precision and sensitivity is circumscribed by absorbing and non-absorbing components found in wet steam. Using the dual-wavelength absorption technique (DWAT), the accuracy of measurements has been greatly improved. Pressure and temperature's influence on the absorption of water vapor is reduced to insignificance by a non-dimensional correction factor. Quantification of dryness relies on the values of water vapor concentration and wet steam mass within the steam cell. A four-stage separating and throttling calorimeter, coupled with a condensation rig, is used to validate the DWAT dryness measurement approach. The dryness measurement system, employing an optical method, demonstrates 1% accuracy for wet steam dryness levels and operating pressures from 1 to 10 bars.
Recent years have witnessed the widespread use of ultrashort pulse lasers in the electronics industry, replication tools, and other applications for superior laser machining. However, the major limitation of this processing is its low effectiveness, especially when a considerable number of laser ablation processes are required. The analysis of a novel beam-splitting method, based on cascaded acousto-optic modulators (AOMs), is presented in this paper. The same propagation direction is shared by all beamlets produced from a laser beam split by cascaded AOMs. There is independent control over the switching of each beamlet and the adjustment of its pitch angle. To verify the high-speed control (1 MHz switching rate), high-energy utilization rate (>96% across three AOMs), and the uniformity of the energy splitting (nonuniformity of 33%), a setup of three cascaded AOM beam splitters was configured. This scalable approach enables high-quality and efficient processing of arbitrary surface structures, irrespective of their complexity.
Using the co-precipitation approach, a cerium-doped lutetium yttrium orthosilicate (LYSOCe) powder was successfully synthesized. The lattice structure and luminescence characteristics of LYSOCe powder, affected by varying Ce3+ doping concentrations, were investigated using X-ray diffraction (XRD) and photoluminescence (PL). X-ray diffraction analysis established that the LYSOCe powder's crystal structure maintained its original form following ion incorporation. Photoluminescence (PL) experiments on LYSOCe powder indicate superior luminescence performance at a Ce doping concentration of 0.3 mol%. Measurements were undertaken on the samples' fluorescence lifetime, and the outcomes indicate that LYSOCe displays a short decay time. LYSOCe powder, doped with 0.3 mol% cerium, was used to prepare the radiation dosimeter. Investigations into the radioluminescence characteristics of the radiation dosimeter were conducted under X-ray exposure, encompassing doses from 0.003 Gy to 0.076 Gy and dose rates from 0.009 Gy/min to 2284 Gy/min. The results highlight a linear correlation and sustained stability in the dosimeter's response. HOpic Data on the radiation responses of the dosimeter at various energy levels were collected through X-ray irradiation, with X-ray tube voltages modulated from 20 to 80 kV. The dosimeter's response to low-energy radiotherapy demonstrates a linear relationship, according to the results. The results observed point to the possibility of using LYSOCe powder dosimeters in both remote radiation therapy and real-time radiation monitoring systems.
For measuring refractive indices, a temperature-insensitive modal interferometer using a spindle-shaped few-mode fiber (FMF) is put forward and its effectiveness is proven. By utilizing a flame, a balloon-shaped interferometer, composed of a definite length of FMF fused between two defined lengths of single-mode fiber, is converted into a spindle shape, increasing its sensitivity. Bending the fiber results in light escaping the core, exciting higher-order modes in the cladding and causing interference with the core's four modes within the FMF. Consequently, the sensor exhibits heightened responsiveness to variations in the surrounding refractive index. The findings of the experiment indicate a peak sensitivity of 2373 nm/RIU, observed within the 1333 to 1365 nm range. Because the sensor is unaffected by temperature, the problem of temperature cross-talk is solved. Not only does the sensor feature a compact design, effortless manufacturing, low energy dissipation, and exceptional mechanical strength, but it also holds significant promise for applications in chemical production, fuel storage, environmental monitoring, and other related sectors.
Laser damage experiments on fused silica frequently monitor damage initiation and growth by imaging the sample surface, overlooking the structural characteristics of the sample's bulk morphology. In fused silica optics, a damage site's depth is believed to be directly proportional to its equivalent diameter. Undeniably, some sites of damage manifest phases with no alteration in their diameter, yet experience growth within their bulk structure, unconnected to their surface. The damage diameter's proportional relationship does not provide an accurate representation of the growth of these locations. We propose an accurate damage depth estimator, grounded in the principle that the volume of a damage site is directly proportional to the intensity of the light scattered by it. Analyzing pixel intensity, an estimator elucidates the changes in damage depth during successive laser irradiations, encompassing periods where variations in depth and diameter are uncorrelated.
Hyperbolic material -M o O 3, excelling in its hyperbolic bandwidth and polariton lifetime, surpasses other similar materials, thereby designating it a perfect candidate for broadband absorption. The gradient index effect is employed in this work to conduct a theoretical and numerical investigation into the spectral absorption of an -M o O 3 metamaterial. Absorbance measurements at 125-18 m, with transverse electric polarization, indicate the absorber has a mean spectral absorbance of 9999%. Transverse magnetic polarization of incident light results in a blueshifted broadband absorption region in the absorber, achieving significant absorption at wavelengths between 106 and 122 nanometers. We find that the simplified geometric model of the absorber, via the equivalent medium theory, demonstrates that the surrounding medium's refractive index match with that of the metamaterial leads to broad absorption. Through calculations, the spatial distributions of the electric field and power dissipation density within the metamaterial were examined, providing clarity on the location of the absorption. Beyond this, the impact of the pyramid structure's geometric properties on its ability to absorb broadband frequencies was investigated. HOpic Lastly, we investigated how the polarization angle altered the spectral absorption pattern of the -M o O 3 metamaterial. This research aims to advance the design of broadband absorbers and related devices based on anisotropic materials, fostering significant progress in solar thermal utilization and radiative cooling strategies.
Recent years have witnessed a surge of interest in ordered photonic structures, or photonic crystals, thanks to their potential applications, which are, in turn, reliant on mass-production-friendly fabrication techniques. Light diffraction was employed in this paper to study the order in photonic colloidal suspensions of core-shell (TiO2@Silica) nanoparticles dispersed in ethanol and water solutions. Photonic colloidal suspensions display a more pronounced ordering pattern evident in light diffraction measurements, being stronger in ethanol suspensions than in water suspensions. Interferential processes, significantly facilitated by the ordered and correlated arrangement of scatterers (TiO2@Silica), stem from the strong and long-range influence of Coulomb interactions, leading to light localization.
Recife, Pernambuco, Brazil, hosted the 2022 Latin America Optics and Photonics Conference (LAOP 2022), the major international gathering organized by Optica in Latin America, a decade after the conference's inaugural event in 2010. HOpic LAOP, held biennially (excluding 2020), strives unequivocally to elevate Latin American expertise in optics and photonics research and support the regional research community. The 6th edition in 2022 included a significant technical program, showcasing recognized experts across a variety of fields critical to Latin America, from biophotonics to cutting-edge 2D materials research.