A multi-stage amplifier system based on high-power end-pumped two-segmented Nd:YVO4 is developed, which realizes the effective beam quality management in high-power laser. Because of the severe

A multi-stage amplifier system based on high-power end-pumped two-segmented Nd:YVO4 is developed, which realizes the effective beam quality management in high-power laser. Because of the severe thermal effect caused by high-power end pumping, both the appropriate crystal and beam filling factor (the ratio of the laser beam radius to the pump beam radius) are important in the amplifier. The multi-segmented doped crystal is controlled in cooperation with beam filling factor to realize high output power and maintain good beam quality. To study the thermal effect in the end-pumped crystal, the temperature distribution of end-pumped single-segmented and two-segmented Nd:YVO4 are theoretically calculated. In the experiment, a probe laser is employed to measure the spherical aberration coefficient and the beam quality of the laser at the rear end of the two end-pumped crystals respectively, and the experimental results are in good agreement with the theoretical results. In the power amplification, a seed laser is employed in the experiment. The appropriate gain medium and beam filling factor are determined by considering the spherical aberration coefficient, beam quality and power extraction efficiency. Based on the reasonable layout of the power amplification for each stage amplifier, the multi-stage amplifier system outputs 280.2W picosecond laser with the beam quality factor of Mx2=1.28 and My2=1.32.show less

In this study, we propose a ghost imaging method capable of penetrating dynamic scattering media through a multi-polarization fusion mutual supervision network (MPFNet). The MPFNet effectively p

In this study, we propose a ghost imaging method capable of penetrating dynamic scattering media through a multi-polarization fusion mutual supervision network (MPFNet). The MPFNet effectively processes one-dimensional light intensity signals collected under both linear and circular polarization illumination. By employing a multi-branch fusion architecture, the network excels at extracting multi-scale features and capturing contextual information. Additionally, a multi-branch spatial-channel cross-attention module optimizes the fusion of multi-branch feature information between the encoder and the decoder. This synergistic fusion of reconstruction results from both polarization states yields reconstructed object images with significantly enhanced fidelity compared to ground truth. Moreover, leveraging the underlying physical model and utilizing the collected one-dimensional light intensity signal as the supervisory labels, our method obviates the need for pre-training, ensuring robust performance even in challenging, highly scattering environments. Extensive experiments conducted on free space and underwater environments have demonstrated that the proposed method holds significant promise for advancing high-quality ghost imaging through dynamic scattering media.show less

We propose a Phong shading approximation, which gives the amplitude of each point inside the triangle through linear interpolation within the framework of self-similarity segmentation and affine

We propose a Phong shading approximation, which gives the amplitude of each point inside the triangle through linear interpolation within the framework of self-similarity segmentation and affine transformation in polygon-based computer-generated holography. Shading is important as it reflects the geometric properties of the objects. To accurately represent the geometric properties of objects in three-dimensional space, the method involves calculating the amplitude distribution on each triangle and maintaining a complete analytical framework, with the edges of the reconstructed polygons nearly unobservable. Numerical simulations and optical reconstructions demonstrate that the proposed method successfully addresses the issue of edge discontinuity on polygonal surfaces.show less

Whispering gallery resonator (WGR) represent a promising avenue for the miniaturization of optical devices, while cascaded optical parameter oscillator (OPO) processes haven’t been realized in W

Whispering gallery resonator (WGR) represent a promising avenue for the miniaturization of optical devices, while cascaded optical parameter oscillator (OPO) processes haven’t been realized in WGR, to the best of our knowledge. We presents a microdisk with quality factors up to 3.2×107, then embed two quasi phase-matching (QPM) structures inside it to demonstrate cascaded OPO. The cascaded OPO exhibits the same idler light output with the threshold 32.7mW at 36℃ (1063.8nm→1566.6nm+3314.6nm/1566.6nm→2970.4nm+3314.6nm), while operating threshold of OPOwithout cascade process is 4.32mW. Moreover, diverse cascaded processes are observed, with the longest output wavelength reaching 4802.9 nm. Our results suggest the potential for a low-threshold cascade OPO based on WGR.show less