A method for capturing the seven-dimensional light field structure is presented, followed by its translation into information that resonates with human perception. The spectral cubic illumination method, in its objective characterization, measures the measurable counterparts of diffuse and directed light's perceptually relevant aspects across different time periods, locations, colors, directions, along with the environment's response to sunlight and sky conditions. We tested it in the real world, recording the contrasts between light and shadow under a sunny sky, and the changes in light levels between clear and overcast 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. Employing a neural network (NN), this paper develops a cost-effective demodulation system applicable to FBG array sensors. Stress fluctuations acting upon the FBG array sensor are converted by the array waveguide grating (AWG) into varying intensities across distinct channels. These intensity values are fed to an end-to-end neural network (NN) model, which simultaneously calculates a complex nonlinear relationship between intensity and wavelength to precisely determine the peak wavelength. A low-cost approach for data augmentation is presented to address the bottleneck of limited data size often encountered in data-driven methods, thereby enabling the neural network to still attain superior performance with a small-scale dataset. In conclusion, the FBG array sensor-driven demodulation system enables a reliable and efficient method for monitoring numerous points on expansive structures.
We have experimentally demonstrated and proposed an optical fiber strain sensor with both high precision and a wide dynamic range, leveraging a coupled optoelectronic oscillator (COEO). The COEO is characterized by the fusion of an OEO and a mode-locked laser, each of which uses the same optoelectronic modulator. The oscillation frequency of the laser, determined by the interplay of the two active loops, aligns with the 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. Enhanced sensitivity is achievable through the integration of higher-order harmonics, due to their cumulative impact. Our proof-of-concept experiment aimed to validate the core functionality. One can achieve a dynamic range as high as 10000. Sensitivity values of 65 Hz/ at 960MHz and 138 Hz/ at 2700MHz were determined. The COEO's maximum frequency drift within 90 minutes is 14803Hz for 960MHz and 303907Hz for 2700MHz, resulting in measurement errors of 22 and 20, respectively. The proposed scheme's strengths lie in its high precision and high speed characteristics. The strain affects the pulse period of an optical pulse generated by the COEO. Consequently, the proposed system holds promise for dynamic strain assessment applications.
Ultrafast light sources have become an essential instrument for accessing and comprehending transient phenomena in the realm of materials science. multiple mediation 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. This presentation highlights and contrasts two strategies for extracting the pertinent harmonic from a high-harmonic generation source, fulfilling the aforementioned goals. The initial approach combines extreme ultraviolet spherical mirrors with transmission filters. The second approach utilizes a normal-incidence spherical grating. Both solutions, focusing on time- and angle-resolved photoemission spectroscopy with photon energies ranging from 10 to 20 electronvolts, are also applicable to a broader spectrum of experimental techniques. Focusing quality, photon flux, and temporal broadening characterize the two approaches to harmonic selection. Focusing gratings provide much greater transmission than mirror-plus-filter setups, demonstrating 33 times higher transmission at 108 eV and 129 times higher at 181 eV, coupled with only a slight widening of the temporal profile (68%) and a somewhat larger spot size (30%). Our experimental approach reveals the implications of the trade-off between designing a single grating normal incidence monochromator and using filters. Thus, it offers a platform for choosing the most suitable method across multiple sectors needing a simple-to-implement harmonic selection procedure sourced from high harmonic generation.
Advanced semiconductor technology nodes rely heavily on the accuracy of optical proximity correction (OPC) models to ensure successful integrated circuit (IC) chip mask tape-out, expedite yield ramp-up, and reduce the time to market for products. The precise nature of the model ensures minimal prediction error across the entire chip's layout. The model calibration process crucially requires a pattern set with superior coverage that can address the extensive pattern diversity frequently encountered in a complete chip layout. Colorimetric and fluorescent biosensor Before the final mask tape-out, no existing solutions furnish the effective metrics for determining the coverage sufficiency of the selected pattern set; this could consequently result in increased re-tape out expenditures and a delayed product launch due to repeated model calibrations. To assess pattern coverage prior to obtaining any metrology data, we formulate metrics in this paper. The pattern's internal numerical characteristics, or the potential behavior of its model in simulation, provide the foundation for the metrics. Testing and analysis reveal a positive association between these metrics and the degree of accuracy in the lithographic model. Furthermore, an incremental selection method, informed by the simulation errors of patterns, is introduced. A reduction of up to 53% occurs in the verification error range of the model. OPC recipe development processes are favorably affected by the efficiency improvements derived from pattern coverage evaluation methods for OPC model construction.
The remarkable frequency-selective properties of frequency selective surfaces (FSSs), a modern artificial material, open up exciting possibilities within engineering applications. Employing FSS reflection, this paper describes a flexible strain sensor. This sensor can readily conform to the surface of an object and withstand deformation under mechanical load. A variation in the FSS structure invariably translates to a change in the original operating frequency. By evaluating the variance in electromagnetic characteristics, a real-time assessment of the strain on an object is attainable. This research describes an FSS sensor, which functions at 314 GHz and presents an amplitude of -35 dB, and shows favourable resonance properties within the Ka-band. The FSS sensor's sensing performance is outstanding, given its quality factor of 162. The sensor's role in detecting strain within the rocket engine case involved both statics and electromagnetic simulation. A 164% radial expansion of the engine case correlated to a roughly 200 MHz shift in the sensor's operating frequency. This shift exhibits a strong linear dependence on the deformation under different load conditions, permitting precise strain monitoring of the case. SN-38 purchase In this investigation, we performed a uniaxial tensile test on the FSS sensor, informed by experimental data. During the test, the FSS's stretching from 0 to 3 mm resulted in a sensor sensitivity of 128 GHz/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. Extensive developmental opportunities abound in this domain.
Coherent systems in long-haul, high-speed dense wavelength division multiplexing (DWDM) networks, affected by cross-phase modulation (XPM), suffer augmented nonlinear phase noise when a low-speed on-off-keying (OOK) optical supervisory channel (OSC) is implemented, ultimately reducing transmission distance. To address OSC-induced nonlinear phase noise, this paper proposes a straightforward OSC coding method. By utilizing the split-step solution of the Manakov equation, the OSC signal's baseband is moved out of the walk-off term's passband, thereby leading to a reduction in the XPM phase noise spectrum density. Testing of the 400G channel over a 1280 km transmission distance showed a 0.96 dB improvement in the optical signal-to-noise ratio (OSNR) budget, achieving performance virtually indistinguishable from the absence of optical signal conditioning.
Highly efficient mid-infrared quasi-parametric chirped-pulse amplification (QPCPA) is numerically demonstrated using a 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. Mid-infrared QPCPA's resistance to variations in phase-mismatch and pump intensity is assured by the suppression of back conversion. The QPCPA, based on the SmLGN, will offer a highly effective method for transforming existing, sophisticated 1-meter intense laser pulses into mid-infrared ultrashort pulses.
Within this manuscript, we present a narrow linewidth fiber amplifier, utilizing a confined-doped fiber, and explore its power scaling and beam quality maintaining attributes. The fiber's confined-doped structure, boasting a substantial mode area, and precise Yb-doping within the core, effectively mitigated the competing effects of stimulated Brillouin scattering (SBS) and transverse mode instability (TMI).