A Kerr-lens mode-locked laser, featuring an Yb3+-doped disordered calcium lithium niobium gallium garnet (YbCLNGG) crystal, is the subject of this report. At 976nm, a spatially single-mode Yb fiber laser pumps the YbCLNGG laser, resulting in soliton pulses as short as 31 femtoseconds at 10568nm. This laser, utilizing soft-aperture Kerr-lens mode-locking, delivers an average output power of 66 milliwatts and a pulse repetition rate of 776 megahertz. The Kerr-lens mode-locked laser produced a maximum output power of 203 milliwatts for 37 femtosecond pulses, albeit slightly longer than expected, while using an absorbed pump power of 0.74 watts, resulting in a peak power of 622 kilowatts and an optical efficiency of 203 percent.
Commercial applications and academic research have converged on the true-color visualization of hyperspectral LiDAR echo signals, a consequence of remote sensing technological advancements. Spectral-reflectance data is lost in some channels of the hyperspectral LiDAR echo signal due to the emission power limitation of the hyperspectral LiDAR. The color reconstruction process, based on the hyperspectral LiDAR echo signal, is highly susceptible to color cast issues. RI-1 solubility dmso A novel spectral missing color correction approach, grounded in an adaptive parameter fitting model, is introduced in this study to address the existing problem. RI-1 solubility dmso Considering the established intervals lacking in spectral reflectance, the colors calculated in the incomplete spectral integration process are calibrated to faithfully reproduce the desired target colors. RI-1 solubility dmso In the experimental evaluation of the proposed color correction model on hyperspectral images of color blocks, the corrected images display a smaller color difference from the ground truth, which directly correlates with an improvement in image quality and an accurate representation of the target color.
We delve into the steady-state quantum entanglement and steering in an open Dicke model, considering the crucial factors of cavity dissipation and individual atomic decoherence in this paper. Specifically, the independent dephasing and squeezed environments that each atom experiences undermine the validity of the well-established Holstein-Primakoff approximation. Analysis of quantum phase transitions in the context of decohering environments indicates that: (i) In both normal and superradiant phases, cavity dissipation and atomic decoherence boost entanglement and steering between the cavity field and atomic ensemble; (ii) spontaneous emission of individual atoms generates steering between the cavity field and the atomic ensemble, but steering in two directions cannot be realized simultaneously; (iii) the maximum attainable steering in the normal phase surpasses that in the superradiant phase; (iv) entanglement and steering between the cavity output field and atomic ensemble are notably greater than those with the intracavity field, and simultaneous steering in two directions is achievable despite identical parameter settings. In the open Dicke model, individual atomic decoherence processes are shown by our findings to contribute to the unique features of quantum correlations.
Polarization information in images with reduced resolution becomes harder to discern, impeding the identification of small targets and weak signals. The polarization super-resolution (SR) method presents a possible way to deal with this problem, with the objective of generating a high-resolution polarized image from a low-resolution one. The pursuit of super-resolution (SR) utilizing polarization data introduces a greater degree of difficulty compared to intensity-only approaches. This added complexity arises from the requirement to simultaneously reconstruct both polarization and intensity information, and the handling of multiple channels with complex, non-linear interconnections. This research paper delves into the issue of polarized image degradation and introduces a deep convolutional neural network for polarization super-resolution reconstruction, drawing on two different models of degradation. Effective intensity and polarization information restoration has been confirmed for the network structure, validated by the well-designed loss function, enabling super-resolution with a maximum scaling factor of four. The empirical results show the proposed technique's superior performance compared to alternative super-resolution approaches, distinguishing itself in both quantitative evaluation and visual aesthetic appraisal, across two distinct degradation models with varying scaling factors.
For the first time, an analysis of the nonlinear laser operation within an active medium formed by a parity-time (PT) symmetric structure situated inside a Fabry-Perot (FP) resonator is demonstrated in this paper. A theoretical model incorporates the reflection coefficients and phases of the FP mirrors, the symmetric structure period of the PT, the primitive cell count, and the saturation effects of gain and loss. Laser output intensity characteristics are calculated using the modified transfer matrix method. Mathematical results demonstrate that the phase alignment of the FP resonator's mirrors is crucial in controlling the output intensity levels. Consequently, for a definite proportion between the grating period and the operating wavelength, a bistable effect is demonstrably achievable.
This study created a method to simulate sensor responses and verify its success in spectral reconstruction using a system of tunable LEDs. Improved spectral reconstruction accuracy is achievable in a digital camera setting, as indicated by studies, by incorporating multiple channels. However, the manufacturing process and validation of sensors with engineered spectral sensitivities presented significant obstacles. In conclusion, the availability of a fast and reliable validation method was preferred in the evaluation phase. For replicating the designed sensors, this investigation introduced two unique simulation approaches: the channel-first method and the illumination-first method, both utilizing a monochrome camera and a spectrum-tunable LED illumination system. In the channel-first methodology applied to an RGB camera, three extra sensor channels' spectral sensitivities were optimized theoretically, subsequently simulated by matching corresponding LED system illuminants. Through the illumination-first method, the spectral power distribution (SPD) of the lights using the LED system was improved, and the associated extra channels could subsequently be ascertained. Practical experiments demonstrated the efficacy of the proposed methods in simulating extra sensor channel responses.
High-beam quality 588nm radiation was successfully generated using a frequency-doubled crystalline Raman laser. A YVO4/NdYVO4/YVO4 bonding crystal, serving as the laser gain medium, has the capability of expediting thermal diffusion. A YVO4 crystal was used for the purpose of intracavity Raman conversion, and an LBO crystal was utilized for achieving second harmonic generation. With 492 watts of incident pump power and a 50 kHz pulse repetition frequency, a 285-watt 588-nm laser power output was achieved. The 3-nanosecond pulse duration corresponds to a diode-to-yellow laser conversion efficiency of 575% and a slope efficiency of 76%. A single pulse exhibited an energy level of 57 Joules and a peak power of 19 kilowatts, concurrently. In the V-shaped cavity, which exhibited excellent mode matching, the severe thermal effects of the self-Raman structure were successfully overcome. Combining this with the inherent self-cleaning effect of Raman scattering, the beam quality factor M2 was effectively enhanced, yielding optimal values of Mx^2 = 1207 and My^2 = 1200 at an incident pump power of 492 W.
Results from our 3D, time-dependent Maxwell-Bloch code, Dagon, are shown in this article, focusing on cavity-free lasing in nitrogen filaments. The adaptation of this code, previously used in the modeling of plasma-based soft X-ray lasers, now permits the simulation of lasing within nitrogen plasma filaments. Several benchmarks have been executed to determine the code's predictive capacity, contrasted against experimental and 1D model results. Following that, we investigate the boosting of an externally provided UV light beam inside nitrogen plasma strands. Amplified beam phase serves as a carrier of information on the temporal progression of amplification and collisions within the plasma, along with details of the beam's spatial arrangement and the active filament region. Our analysis leads us to believe that measuring the phase of a UV probe beam, alongside sophisticated 3D Maxwell-Bloch simulations, could represent a highly effective method for discerning electron density and gradient values, average ionization levels, N2+ ion densities, and the extent of collisional interactions within the filaments.
This article presents the modeling of high-order harmonic (HOH) amplification with orbital angular momentum (OAM) in plasma amplifiers, using krypton gas and solid silver targets as the constituent materials. A key aspect of the amplified beam lies in its intensity, phase, and how it breaks down into helical and Laguerre-Gauss modes. The amplification process, while keeping OAM intact, displays a degree of degradation, as demonstrated by the results. Several structures are evident within the profiles of intensity and phase. Our model has characterized these structures, linking them to refraction and interference phenomena within the plasma's self-emission. In summary, these results not only exhibit the prowess of plasma amplifiers in producing high-order optical harmonics that carry orbital angular momentum but also present a means of utilizing these orbital angular momentum-carrying beams as tools to scrutinize the behavior of dense, high-temperature plasmas.
Large-scale, high-throughput manufactured devices with superior ultrabroadband absorption and high angular tolerance are highly desired for thermal imaging, energy harvesting, and radiative cooling applications. Despite sustained endeavors in design and fabrication, the simultaneous attainment of all these desired properties has proven difficult. For the creation of an ultrabroadband infrared absorber, we employ metamaterials comprising epsilon-near-zero (ENZ) thin films on metal-coated, patterned silicon substrates. This design allows absorption in both p- and s-polarization across an angular range from 0 to 40 degrees.