We describe a method for extracting the seven-dimensional light field's structure and converting it into data that is perceptually meaningful. Our spectral cubic illumination method objectively assesses the measurable counterparts of perceptually important diffuse and directional lighting elements, including their temporal, spatial, spectral, directional shifts, and the environmental response to both skylight and sunlight. In the natural environment, we observed how the sun's light differentiates between bright and shadowed regions on a sunny day, and how these differences extend to the differences between sunny and cloudy skies. Our method demonstrates its value in the portrayal of intricate lighting effects on scene and object appearances, notably chromatic gradients.
Large structures' multi-point monitoring benefits substantially from the extensive use of FBG array sensors, owing to their impressive optical multiplexing capacity. Employing a neural network (NN), this paper develops a cost-effective demodulation system applicable to FBG array sensors. The array waveguide grating (AWG) transforms stress variations in the FBG array sensor into corresponding intensity variations across diverse channels. An end-to-end neural network (NN) model then receives these intensities and calculates a complex nonlinear function relating intensity to wavelength to determine the precise peak wavelength. Furthermore, a cost-effective data augmentation technique is presented to overcome the data size constraint, a frequent issue in data-driven approaches, so that the neural network can still achieve excellent results with limited data. In essence, the FBG array-based demodulation system offers a dependable and effective method for monitoring numerous points on extensive structures.
Our proposed and experimentally verified optical fiber strain sensor, boasting high precision and a significant dynamic range, is based on a coupled optoelectronic oscillator (COEO). The COEO, a fusion of an OEO and a mode-locked laser, utilizes a single optoelectronic modulator. The oscillation frequency of the laser is precisely equal to the mode spacing, a consequence of the feedback mechanism between the two active loops. A multiple of the laser's natural mode spacing, which varies due to the cavity's axial strain, is its equivalent. For this reason, quantifying the strain is possible via the oscillation frequency shift measurement. Adopting higher-order harmonics of higher frequencies leads to a more sensitive outcome, due to the cumulative nature of the effect. A proof-of-concept demonstration was executed by us. A figure of 10000 represents the peak dynamic range. Sensitivity measurements of 65 Hz/ at a frequency of 960MHz and 138 Hz/ at a frequency of 2700MHz were taken. Maximum frequency drifts in the COEO, within 90 minutes, are 14803Hz for 960MHz and 303907Hz for 2700MHz, translating to measurement errors of 22 and 20. The high precision and high speed features are inherent in the proposed scheme. An optical pulse with a period contingent upon the strain can be generated by the COEO. Thus, the proposed configuration presents applications for dynamic strain evaluation.
Transient phenomena in material science are now within the grasp of researchers, thanks to the critical role of ultrafast light sources. TOPK inhibitor Despite the desire for a simple and readily implementable method for harmonic selection, exhibiting both high transmission efficiency and preserving pulse duration, a significant challenge persists. Two distinct procedures for selecting the desired harmonic from a high-harmonic generation source are compared and analyzed, ensuring the achievement of the outlined goals. The initial approach is founded on the integration of extreme ultraviolet spherical mirrors with transmission filters; the second approach uses a spherical grating incident at normal. Employing photon energies in the 10-20 eV range, both solutions address time- and angle-resolved photoemission spectroscopy, demonstrating applicability in other experimental contexts as well. The two methods of harmonic selection are distinguished by their emphasis on focusing quality, photon flux, and temporal broadening. Transmission through a focusing grating is considerably higher than with the mirror-filter combination (33 times higher for 108 eV, 129 times higher for 181 eV), with only a modest temporal broadening (68%) and a relatively larger focal spot (30% increase). This study, through its experimental design, explores the trade-off between a single grating normal incidence monochromator and the practicality of using filters. Subsequently, it provides a base for selecting the most applicable strategy across several domains where an effortlessly implemented harmonic selection from the high harmonic generation phenomenon is required.
For advanced semiconductor technology nodes, integrated circuit (IC) chip mask tape out, successful yield ramp-up, and the speed of product introduction are critically contingent upon the accuracy of optical proximity correction (OPC) modeling. The precision of the model is directly linked to a small prediction error across the entire chip layout. The substantial pattern variation inherent in a complete chip layout necessitates selecting a pattern set with good coverage during model calibration. TOPK inhibitor Existing solutions presently lack the effective metrics for evaluating the sufficiency of the selected pattern set's coverage before a real mask tape-out, leading to potentially higher re-tape out costs and delayed product time-to-market due to repeated model calibrations. Metrics for evaluating pattern coverage, to be used before any metrology data is obtained, are presented in this paper. Evaluation metrics are predicated on either the intrinsic numerical representation of the pattern, or its potential simulation outcome. Experimental results display a positive connection between these metrics and the accuracy of the lithographic model's predictions. Furthermore, an incremental selection method, informed by the simulation errors of patterns, is introduced. The model's verification error range can be minimized by up to 53%. By improving the efficiency of OPC model construction, pattern coverage evaluation methods contribute favorably to the complete OPC recipe development process.
In engineering applications, frequency selective surfaces (FSSs), advanced artificial materials, are distinguished by their impressive frequency selection capabilities. We introduce, in this paper, a flexible strain sensor. This sensor, which uses FSS reflection, can conform to the surface of an object and bear the mechanical strain from an applied load. Upon modification of the FSS architecture, the formerly utilized operating frequency will be altered. The strain level of an object can be tracked in real time by analyzing the discrepancy in its electromagnetic performance. This study presents an FSS sensor operating at 314 GHz, characterized by a -35 dB amplitude and displaying favourable resonance within the Ka-band. The FSS sensor's sensing performance is outstanding, given its quality factor of 162. The sensor's application in detecting strain within a rocket engine casing was facilitated by statics and electromagnetic simulations. The engine case's 164% radial expansion caused a notable 200 MHz shift in the sensor's operating frequency. The frequency shift displays a consistent linear correlation with the strain, making this method suitable for accurate strain detection across diverse loads. TOPK inhibitor Utilizing experimental data, we investigated the FSS sensor through a uniaxial tensile test in this study. The sensitivity of the sensor reached 128 GHz/mm when the FSS was stretched between 0 and 3 mm during the test. The FSS sensor's high sensitivity and strong mechanical properties further corroborate the practical significance of the FSS structure developed within the confines of this paper. The field provides considerable room for future development and expansion.
Long-haul, high-speed dense wavelength division multiplexing (DWDM) coherent systems, subject to cross-phase modulation (XPM), experience increased nonlinear phase noise when utilizing a low-speed on-off-keying (OOK) format optical supervisory channel (OSC), thereby curtailing the transmission span. To address OSC-induced nonlinear phase noise, this paper proposes a straightforward OSC coding method. The Manakov equation's split-step solution procedure facilitates the up-conversion of the OSC signal's baseband beyond the walk-off term's passband, thus diminishing the spectrum density of XPM phase noise. The experimental results for the 400G channel across 1280 km of transmission show a 0.96 dB gain in the optical signal-to-noise ratio (OSNR) budget, a performance almost on par with the setup without optical signal conditioning.
Numerical studies demonstrate high efficiency in mid-infrared quasi-parametric chirped-pulse amplification (QPCPA) for the recently developed Sm3+-doped La3Ga55Nb05O14 (SmLGN) crystal. Broadband absorption of Sm3+ within idler pulses, at a pump wavelength close to 1 meter, allows QPCPA for femtosecond signal pulses centered around 35 or 50 nanometers, with conversion efficiency approaching the quantum limit. Due to the prevention of back conversion, mid-infrared QPCPA displays a high degree of resilience to both phase-mismatch and fluctuations in pump intensity. By utilizing the SmLGN-based QPCPA, a potent conversion method for transforming currently well-developed intense laser pulses at 1 meter wavelength into mid-infrared ultrashort pulses will be realized.
This study details the construction of a narrow linewidth fiber amplifier utilizing confined-doped fiber, focusing on its power scaling and beam quality maintenance properties. Benefiting from both the large mode area of the confined-doped fiber and the precise control of the Yb-doped region within the core, the stimulated Brillouin scattering (SBS) and transverse mode instability (TMI) were efficiently balanced.