A method is presented to capture the seven-dimensional structure of the light field, culminating in its interpretation into information pertinent to human perception. Objective quantification of perceptually relevant components of diffuse and directional illumination, as defined by a spectral cubic model, encompasses variations over time, space, color, and direction and the environment's response to the sky and sunlight. Using a real-world setting, we captured the contrast in illumination between bright and shadowed spots on a sunny day, and how the light varies from clear to cloudy conditions. We analyze the value enhancement of our method in capturing complex lighting effects on the appearance of scenes and objects, including chromatic gradients.
Large structures' multi-point monitoring benefits substantially from the extensive use of FBG array sensors, owing to their impressive optical multiplexing capacity. A neural network (NN)-based demodulation system for FBG array sensors is presented in this paper, aiming for cost-effectiveness. The FBG array sensor's stress variations are encoded by the array waveguide grating (AWG) into intensity values transmitted across different channels. These intensity values are then provided to an end-to-end neural network (NN) model. The model then generates a complex non-linear function linking transmitted intensity to the precise wavelength, allowing for absolute peak wavelength measurement. To counter the frequent data size problem in data-driven methods, a low-cost data augmentation strategy is introduced. This ensures that the neural network can achieve superior performance even with a smaller dataset. In essence, the FBG array-based demodulation system offers a dependable and effective method for monitoring numerous points on extensive structures.
We have successfully proposed and experimentally validated an optical fiber strain sensor, characterized by high precision and an extensive dynamic range, which utilizes a coupled optoelectronic oscillator (COEO). The COEO is a composite device, incorporating an OEO and a mode-locked laser, both sharing a single optoelectronic modulator. Due to the feedback between the two active loops, the laser's oscillation frequency is equal to its mode spacing. A multiple of the laser's natural mode spacing, a value modified by the applied axial strain to the cavity, constitutes an equivalent. For this reason, quantifying the strain is possible via the oscillation frequency shift measurement. Greater sensitivity is achieved by integrating higher frequency order harmonics, benefitting from their additive effect. A proof-of-concept experiment was undertaken by us. A dynamic range of up to 10000 is attainable. In the experiments, the sensitivities of 65 Hz/ at 960MHz and 138 Hz/ at 2700MHz were measured. Over 90 minutes, the COEO exhibits maximum frequency drifts of 14803Hz at 960MHz and 303907Hz at 2700MHz, resulting in measurement errors of 22 and 20, respectively. The proposed scheme boasts both high precision and high speed. The COEO's output optical pulse exhibits a strain-sensitive pulse period. Thus, the proposed configuration presents applications for dynamic strain evaluation.
Ultrafast light sources are integral to the process of accessing and understanding transient phenomena, particularly within material science. biopsy site identification In contrast to readily achievable goals, the creation of a simple, easily implementable harmonic selection method with high transmission efficiency and maintained pulse duration remains a difficult challenge. Two strategies for obtaining the specific harmonic from a high-harmonic generation source are introduced and contrasted, enabling the attainment of the stated objectives. Combining extreme ultraviolet spherical mirrors with transmission filters constitutes the initial approach, whereas the second approach is predicated on a normal-incidence spherical grating. Both solutions address time- and angle-resolved photoemission spectroscopy, employing photon energies within the 10-20 electronvolt range, and their value extends to other experimental procedures. Two harmonic selection approaches are categorized based on the prioritization of focusing quality, photon flux, and temporal broadening factors. A focusing grating exhibits substantially greater transmission than the mirror-plus-filter configuration (33 times higher at 108 eV and 129 times higher at 181 eV), accompanied by only a modest temporal broadening (68% increase) and a somewhat larger spot size (30% increase). Our empirical findings offer a perspective on the trade-off between a single grating normal incidence monochromator configuration and filter application. It acts as a starting point in the process of picking the most applicable tactic in a multitude of fields where a straightforwardly executable harmonic selection from high harmonic generation is needed.
The key to successful integrated circuit (IC) chip mask tape-out, rapid yield ramp-up, and swift product time-to-market in advanced semiconductor technology nodes rests with the accuracy of optical proximity correction (OPC) modeling. A model's accuracy manifests as a reduced prediction error encompassing the full chip design. During model calibration, achieving optimal coverage across a diverse range of patterns is crucial, given the large pattern variation typically found in a complete chip layout. infection-prevention measures Currently, no existing solutions offer the effective metrics necessary to assess the adequacy of the chosen pattern set's coverage prior to actual mask tape-out, potentially increasing re-tape out expenses and prolonging product market entry times because of multiple model calibration cycles. We construct metrics in this paper for evaluating pattern coverage, preceding the acquisition of any metrology data. Metrics are calculated using either the pattern's intrinsic numerical representation or the predictive modeling behavior it exhibits. The outcomes of the experiments highlight a positive correlation between these performance indicators and the precision of the lithographic model. Furthermore, an incremental selection method, informed by the simulation errors of patterns, is introduced. The model's verification error range is lessened by as much as 53%. The efficiency of OPC model creation can be augmented by employing pattern coverage evaluation methods, contributing positively to the entire OPC recipe development procedure.
Frequency selective surfaces (FSSs), advanced artificial materials, showcase outstanding frequency discrimination, positioning them as a valuable resource for engineering applications. We describe a flexible strain sensor in this paper, one that leverages the reflection properties of FSS. This sensor demonstrates excellent conformal adhesion to an object's surface and a remarkable ability to manage mechanical deformation under a given load. A modification in the FSS structure invariably results in a shift of the initial operational frequency. The object's strain condition can be ascertained in real-time by observing the variance in its electromagnetic properties. Employing a design methodology, this study developed an FSS sensor with a working frequency of 314 GHz. The sensor's amplitude achieves -35 dB, revealing favorable resonance properties within the Ka-band. The FSS sensor boasts a quality factor of 162, signifying exceptional sensing capabilities. The sensor's application in detecting strain within a rocket engine casing was facilitated by statics and electromagnetic simulations. A 164% radial expansion of the engine case led to a roughly 200 MHz shift in the sensor's working frequency, showcasing an excellent linear relationship between frequency shift and deformation across a range of loads, thus enabling accurate case strain detection. NX-5948 price In this investigation, we performed a uniaxial tensile test on the FSS sensor, informed by experimental data. Testing revealed a sensor sensitivity of 128 GHz/mm when the flexible structure sensor (FSS) was stretched between 0 and 3 mm. In conclusion, the FSS sensor's high sensitivity and substantial mechanical properties substantiate the practical value of the designed FSS structure, as presented in this paper. This area of study presents vast opportunities for development.
Due to cross-phase modulation (XPM), long-haul, high-speed dense wavelength division multiplexing (DWDM) coherent systems utilizing a low-speed on-off-keying (OOK) format optical supervisory channel (OSC) encounter additional nonlinear phase noise, thus limiting the attainable transmission distance. To address OSC-induced nonlinear phase noise, this paper proposes a straightforward OSC coding method. The Manakov equation's split-step solution involves up-converting the OSC signal's baseband, relocating it beyond the walk-off term's passband, thereby decreasing the XPM phase noise spectral density. The 1280 km transmission of the 400G channel shows a 0.96 dB boost in optical signal-to-noise ratio (OSNR) budget in experimental results, achieving practically the same performance as the scenario without optical signal conditioning.
Numerical results showcase the highly efficient mid-infrared quasi-parametric chirped-pulse amplification (QPCPA) characteristics of a recently developed Sm3+-doped La3Ga55Nb05O14 (SmLGN) crystal. At a pump wavelength near 1 meter, broadband absorption of Sm3+ on idler pulses facilitates QPCPA for femtosecond signal pulses centered at 35 or 50 nanometers, achieving conversion efficiency approaching the theoretical limit. Mid-infrared QPCPA's resistance to phase-mismatch and pump-intensity alterations is a direct consequence of the suppression of back conversion. An efficient methodology for transforming currently well-established intense laser pulses from 1 meter to mid-infrared ultrashort pulses will be established through the utilization of the SmLGN-based QPCPA.
A confined-doped fiber-based narrow linewidth fiber amplifier is presented in this manuscript, along with an investigation into its power scalability and beam quality preservation. Through the combination of a large mode area in the confined-doped fiber and precise control over the Yb-doping within the core, the competing effects of stimulated Brillouin scattering (SBS) and transverse mode instability (TMI) were successfully balanced.