In this Letter, we demonstrate high-energy and high-peak-power nanosecond pulse generation aiming at the 2.94 μm water absorption peak, from a 980 nm diode-clad-pumped actively Q-switched Er3+/D

In this Letter, we demonstrate high-energy and high-peak-power nanosecond pulse generation aiming at the 2.94 μm water absorption peak, from a 980 nm diode-clad-pumped actively Q-switched Er3+/Dy3+ codoped fluoride fiber oscillator, for the first time. Operating at the 2943 nm wavelength locked by a diffraction grating in a Littrow configuration, stable Q-switching with the shortest temporal width of 41 ns has been obtained at a low repetition rate of 100 Hz. The maximum pulse energy of 108 μJ and peak power of 2.48 kW are primarily limited by the thermal damage of the bare fluoride fiber facet for pump coupling, and represent the records of pulsed fiber oscillators around 2.94 μm, to the best of our knowledge. This advanced nanosecond laser source provides an optional promising tool for laser medical applications.show less

Imaging through scattering media remains a formidable challenge in optical imaging. Exploiting the memoryeffect presents new opportunities for non-invasive imaging through scattering medium by l

Imaging through scattering media remains a formidable challenge in optical imaging. Exploiting the memoryeffect presents new opportunities for non-invasive imaging through scattering medium by leveraging specklecorrelations. Traditional speckle correlation imaging often utilizes random phase as the initial phase, leadingto challenges such as convergence to incorrect local minima and the inability to resolve ambiguities inobject orientation. Here, a novel method for high-quality reconstruction of single-shot scattering imaging isproposed. By employing the initial phase obtained from bispectral analysis in the subsequent phase retrievalalgorithm, the convergence and accuracy of the reconstruction process are notably improved. Furthermore,a robust search technique based on an image clarity evaluation function successfully determines the optimalreconstruction size. The study demonstrates that the proposed method can obtain high-quality reconstructedimages compared with the existing scattering imaging approaches. This innovative approach to non-invasivesingle-shot imaging through strongly scattering media shows potentials for applications in scenarios involvingmoving objects or dynamic scattering imaging scenes.show less

Single-pixel cameras maintain advantages over conventional array sensors including a higher signal-to-noise ratio and fewer measurements. However, the existing single-pixel imaging (SPI) and sen

Single-pixel cameras maintain advantages over conventional array sensors including a higher signal-to-noise ratio and fewer measurements. However, the existing single-pixel imaging (SPI) and sensing techniques suffer from low imaging resolution, poor reconstruction quality and heavy computation cost, limiting their widespread applications. To address these challenges, we propose a large-scale single-pixel imaging and sensing (SPIS) technique that enables megapixel SPI and highly-efficient sensing with a low sampling rate. Specifically, we first scan and sample the entire scene using small-size optimized patterns to obtain information-coupled measurements. Compared to the conventional full-size patterns, small-size optimized patterns achieve higher sampling performance with one order of magnitude fewer pattern parameters. Next, the coupled measurements are processed through a Transformer-based encoder to extract high-dimensional features, followed by a task-specific plug-and-play decoder for imaging or sensing. Additionally, considering that the regions with rich textures and edges are more difficult to reconstruct, we introduced a novel uncertainty-driven self-adaptive loss (UDL) function to reinforce the network's attention to these regions, thereby improving the imaging and sensing performance. Extensive experiments demonstrate that our SPIS achieves 24.13dB megapixel SPI at a sampling rate of 3% and achieves state-of-the-art image-free single-pixel sensing performance with one order of magnitude less data bandwidth.show less

Double-cone ignition (DCI) scheme is a promising novel ignition method, which is expected to greatly save the driver energy and enhance the robustness of the implosion process. In this paper, ab

Double-cone ignition (DCI) scheme is a promising novel ignition method, which is expected to greatly save the driver energy and enhance the robustness of the implosion process. In this paper, ablation of the inner surface of the cone by the hard X-ray from coronal Au plasma is studied via radiation-hydrodynamics simulations. It is found that the X-ray ablation of the inner wall will form strong pre-plasma, which will significantly affect the implosion process and cause the Au plasma to mix with the fuel, leading to ignition failure. The radiation and pre-ablation intensities in the system are estimated, and the evolution of areal density, ion temperature and the distribution of Au ions are analyzed. Additionally, the mixing of Au in CH at collision is quantified. Then, a scheme to reduce the X-ray pre-ablation by replacing the gold cone with a tungsten cone is proposed, showing that it is effective in reducing high-Z mixing and improving collision results.show less