Conventional mechanical scanning LiDAR systems are often constrained by their large size, limited scanning speed, and fixed resolution. Liquid crystal polarization gratings (LCPG) present a promising alternative as non-mechanical beam deflectors. However, their inherent limitation of discrete angular deflection restricts their application in continuous scanning imaging. Here, we propose and experimentally demonstrate a novel Frequency Modulated Continuous Wave (FMCW) LiDAR architecture that integrates cascaded LCPGs with galvanometers. This hybrid strategy synergizes the coarse steering of LCPG with the continuous fine scanning of galvanometers, achieving a large field of view (FoV) of ±48° alongside simultaneous ranging and velocimetry. Crucially, we address the long-standing challenge of echo signal reception caused by the polarization-dependent diffraction of LCPGs in FMCW systems via a compact coaxial transceiver design featuring a perforated mirror and a quarter-wave plate (QWP). The proof-of-concept prototype validates high-fidelity 3D point cloud reconstruction for both static and dynamic targets. Furthermore, the system incorporates a dynamically reconfigurable "staring" mode, significantly enhancing the spatial resolution for regions of interest. To the best of our knowledge, this work represents the first successful integration of LCPG into an FMCW LiDAR framework. This technology offers a compelling pathway for next-generation autonomous navigation and remote sensing platforms requiring high precision and robustness.

Post-compression based on self-phase modulation (SPM) is widely used for femtosecond pulse shortening. However, the influence of the driving beam wavefront on different compression schemes remains unexplored. Using a Yb-doped fiber laser (230 fs, 200 kHz), we experimentally compare pulse compression in a hollow-core fiber (HCF) and a multi-pass cell (MPC). The HCF compresses pulses to 27 fs with an efficiency of approximately 55% and improves beam quality via modal filtering. The MPC achieves 34 fs pulses with an efficiency of approximately 90% and exhibits a quasi-waveguide mode-filtering effect, substantially enhancing output wavefront quality even when the input wavefront is poor. High-harmonic generation (HHG) experiments show that the HCF-driven source yields a higher photon flux (1.25 × 10¹¹ photons/s) compared to the MPC-driven source (4.95 × 10¹⁰ photons/s). Using a second Yb-doped fiber laser (223 fs, 100 kHz), a cascaded MPC–HCF scheme generates 7.5 fs pulses with an overall efficiency of approximately 70%, enabled by employing a larger-core HCF in the second compression stage. HHG experiments performed with the compressed pulses demonstrate that spatial phase evolution is a critical parameter in post-compression design for such applications.

At the low-coherence Kunwu laser facility with a 0.6% bandwidth, we experimentally studied the laser absorption efficiency of laser-target coupling at intensities of (3-5) & times; 1014 W cm-2. To characterize side scattering across a wide angular range, we developed a novel radiochromic film-based diagnostic system, which enables continuous spatial mapping over approximately pi steradians for the first time. The results indicate a substantial reduction in total loss rate (by more than three times) when compared to a monochromatic laser. We focused on analyzing the influence of laser bandwidth on stimulated Brillouin scattering and stimulated Raman scattering (SRS). Notably, we found that the broadband laser enhances SRS at high intensities, which is contrary to the results obtained at low intensities. These results highlight the role of bandwidth as a quantitative control parameter for improving laser-plasma coupling, which is of particular significance for advancing direct-drive inertial confinement fusion.

The equation of state (EOS) of hydrogen isotopes under extreme conditions is fundamental to planetary science and inertial confinement fusion (ICF), yet experimental constraints across broad thermodynamic regimes remain sparse. We report laser-driven shock measurements on hydrogen and deuterium statically precompressed to record pressures of 5.1 and 6.2 GPa, respectively. By coupling an integrated static-dynamic compression platform with a rigorous precompression-corrected impedance-matching framework, we extract high-precision pressure-density-temperature data up to 158.8 GPa for H2 and 281.9 GPa for D2. These measurements systematically expand the accessible phase space, exhibiting excellent agreement with a wide-range EOS model and establishing stringent benchmarks for modeling giant planetary interiors and ICF plasmas.

We report on the investigation of laser-induced plasma generation mechanisms in laser-aerosols interaction with dry Cu nano-aerosols of different sizes as the samples. The energy transfer mechanism is firstly analyzed based on the comparison of electron temperature between pure air and that containing aerosols, and the breakdown energy threshold for particles with respect to aerosol density. It is inferred that both laser-particle interaction and plasma-particle interaction exist in laser-induced plasma generation in nano-aerosols. The plasma-particle interaction becomes dominant for the cases with low aerosol density. Specifically, the plasma plays dual roles in interaction with aerosols—atomization and excitation. According to the electron temperature drop for the case with aerosols compared with pure air, we roughly estimated the energy loss of plasma and found that it is not enough to fully atomize the particles. On this basis, the smaller particles, which can absorb more energy because of the larger relative surface and more absorbing entities presenting in the plasma, are helpful to achieve higher LIBS signal intensity, electron temperature and density. This work is useful in understanding the mechanism of laser-aerosol interaction, which would be of importance in the wide applications of laser-induced plasma generation from aerosols including radiation generation, aerosol detection, and the dual-pulse LIBS technique.

We compared the performance of two post-compression techniques, a gas-filled hollow-core fiber (HCF) and a multi-pass cell (MPC), using a high-power ytterbium-doped fiber laser. The HCF produced 27 fs pulses from 230 fs inputs at >50% efficiency, whereas the MPC achieved 34 fs pulses with significantly higher efficiency (>88%). Both results aligned well with numerical simulations. Crucially, spatial wavefront analysis revealed that the HCF acts as a modal filter, improving beam quality, whereas the MPC introduces aberrations through cumulative mirror errors. Furthermore, we characterize the photon flux of high harmonic generation driven by the post-compressed pulses from the HCF and MPC. These finding highlights that post-compression technique based on self-phase modulation is efficient for the intensity boosting of femtosecond laser system, providing opportunities for generating high quality extreme ultraviolet (XUV) sources. In addition, further improvement of spatial wavefront quality is suggested using the HCF as a single compressor or output component of the cascade compressor.

Broadband lasers have become a key strategy for mitigating laser plasma instabilities in inertial confinement fusion, yet their impact on collisional inverse bremsstrahlung (IB) heating remains unclear. Using one-dimensional collisional particle-in-cell simulations, we systematically examine the effect of bandwidth-induced temporal incoherence on IB absorption in Au plasmas. The simulations are first benchmarked against classical absorption theory, verifying that the implemented Coulomb collision model accurately reproduces the theoretical IB heating rate. A direct comparison of the electron temperature evolution in the broadband and monochromatic cases shows that, although spectral broadening introduces transient picosecond-scale oscillations in the heating rate driven by stochastic intensity fluctuations, the long-term averaged heating and net IB absorption remain essentially unchanged.

Laser plasma interaction (LPI) has always been an important research topic in the ignition phase of inertial confinement fusion (ICF). Over the years, researchers have attempted to use various laser beam smoothing schemes and optimized light source solutions to suppress the development of LPI. Among them, low-coherence laser drivers have attracted widespread attention in the fields of laser-plasma physics and laser technology in recent years. Recently, a broadband second harmonic laser facility named “Kunwu” has provided a reliable experimental research platform for the LPI process driven by broadband lasers. Aiming at the strong stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS) in the LPI process of large-scale low-density plasma, forward scattering experiment and near-forward scattering experiment on C8H8 planar film targets driven by broadband laser and narrowband laser under the same conditions are carried out. Based on the “Kunwu” laser facility, two sets of measurement systems are designed, one is centered around fiber-heads and spectrometer, and the other around phototubes and oscilloscope. These systems enable multi-directional precise measurements of scattered lightand a comprehensive analysis of LPI. The main focus is on the comparison of the components and spectral information of the scattering beams between broadband laser and narrowband laser, and it is found that the LPI processes driven by broadband laser and narrowband laser are greatly different. Additionally, preliminary results indicate that broadband laser exhibits a stronger penetration capability than narrowband laser. The time to ablation the target and penetrate the plasma are both nearly 1 ns ahead, with the transmitted energy increased by nearly an order of magnitude. And after penetrating the plasma, there is a smaller spatial divergence angle. These results provide good reference value for better understanding the effect of broadband laser on LPI.

The use of broadband laser technology is a novel approach for inhibiting processes related to laser plasma interactions (LPIs). In this study, several preliminary experiments into broadband-laser-driven LPIs are carried out using a newly established hundreds-of-joules broadband second-harmonic-generation laser facility. Through direct comparison with LPI results for a traditional narrowband laser, the actual LPI-suppression effect of the broadband laser is shown. The broadband laser had a clear suppressive effect on both back-stimulated Raman scattering and back-stimulated Brillouin scattering at laser intensities below 1 × 1015 W cm−2. An abnormal hot-electron phenomenon is also investigated, using targets of different thicknesses.

Aneutronic and nonradioactive properties make the proton-boron fusion a prospective candidate for fusion energy production through reactions following p+$^{11}$B$\rightarrow$3${\alpha}$ (p-$^{11}$B). However, it is difficult to achieve a thermal fusion ignition, since the low reaction cross-sections for center-of-mass energy below $\sim$100 keV. To realize fusion energy gain, it is essential to consider utilization of the maximum cross-section at the resonant peak of p-$^{11}$B fusion, and explore the nuclear reactions in plasma environment. In this work, p-$^{11}$B reactions triggered by interactions between energetic proton beams and laser-ablated boron plasma have been investigated. More than 200 times enhancement of ${\alpha}$ particle emission efficiency (number ratio of escaping ${\alpha}$ particles and boron nuclei) in plasma has been observed, compared with the cold boron. The proton beam transport path modulated by strong electro-magnetic fields in plasma could dominate the enhanced ${\alpha}$ particle generation, due to a longer collisional length. In addition, an ${\alpha}$ particle yield up to 1$\times$10$^{10}$ /sr has been measured via the pitcher-catcher scheme in plasma. This work could benefit understanding of the plasma effects on nuclear reaction dynamics, and also enable opportunities to explore physics in laser fusion associated with advanced fusion fuels.

Abstract The target backsheath field acceleration mechanism is one of the main mechanisms of laser-driven proton acceleration (LDPA) and strongly depends on the comprehensive performance of the ultrashort ultra-intense lasers used as the driving sources. The successful use of the SG-II Peta-watt (SG-II PW) laser facility for LDPA and its applications in radiographic diagnoses have been manifested by the good performance of the SG-II PW facility. Recently, the SG-II PW laser facility has undergone extensive maintenance and a comprehensive technical upgrade in terms of the seed source, laser contrast and terminal focus. LDPA experiments were performed using the maintained SG-II PW laser beam, and the highest cutoff energy of the proton beam was obviously increased. Accordingly, a double-film target structure was used, and the maximum cutoff energy of the proton beam was up to 70 MeV. These results demonstrate that the comprehensive performance of the SG-II PW laser facility was improved significantly.

Solar spicules are small-scale jet-like structures in the lower solar atmosphere. Currently, the formation of these widely distributed structures lacks a complete explanation. It is still unclear whether they play an essential role in corona heating. Here, based on the magnetohydrodynamic scaling transformation relation, we perform experiments with the interaction of a high power laser with a one-dimensional sinusoidal modulated target to model solar spicules. We observe several spicule-like structures with alternating polarity magnetic fields around them. Magnetohydrodynamic simulations with similar parameters show the detail information during the spicules’ formation. The results suggest that the so-called strong pulse model can lead to the formation of the solar spicules. The magnetic reconnection process may also play a part and lead to additional heating and brightening phenomena.

For seawater detection, acoustic means is currently one of the most promising technical means of development. According to the physical properties of acoustic waves, they can be effectively propagated in seawater and ice, and at the interface of different media, there will be reverse acoustic scattering. Using the theory of acoustic propagation in solids, the propagation velocity and refractive index of transverse and vertical, and taking the longitudinal wave as an example, we use the angular spectrum method to solve the fluctuation equation and obtain the beam angle spectrum. Numerical software simulation calculates the time domain characteristics of acoustic scattering at different incidence angles. The effect of evanescent waves on solid sound transmission is also considered. Considering the effect of apocalyptic waves on thin ice on the ocean surface, it provides a theoretical basis for further research on detecting offshore ice using acoustic methods.

Laser-driven magnetic reconnection (LDMR) is an important research topic in the field of high-energy-density physics, such as laboratory astrophysics. In this study, the narrow bandwidth spontaneous light imaging (SLI) technique at the extreme ultraviolet (EUV) band is introduced to detect magnetic reconnection and the jets produced by LDMR. The EUV-based SLI technique will provide reference values for the verification of the results obtained with traditional methods.

Push and pull magnetic reconnection (MR) experiments using high-power laser irradiating a capacitor target with the plates connected by a pair of U-shaped coils are carried out. During the beginning (end) of the laser-target interaction that creates a hot plasma in the region, the rise (fall) stages of the coil currents generates expanding (contracting) magnetic fields that reconnect in the midplane between the coils, resulting in push (pull) MR. Proton radiography and proton ray-tracing simulation are used to track the evolution of the magnetic fields. The proton accumulation and void formation between the coils are related to the oppositely directed current-sheet currents during the push and pull MR stages. The directions of the plasma electron outflows during these two MR phases are obtained by monitoring the soft x-ray emission. Our results suggest that the double-coil capacitor target may be useful for laboratory modeling of fast MR and related phenomena in astrophysical plasmas.

Measurements of Kα line and bremsstrahlung continuous x-ray emission from high-intensity laser-irradiated thin targets are presented. The experiments were performed at the SG-II UP Petawatt laser. Self-standing Sn foils varying thicknesses and Sn foils backed by the thick substrate were irradiated by the laser pulses up to 300 J of energy with peak intensity higher than 1018 W/cm2. A transmission curved crystal spectrometer and a filter-stack spectrometer were used to measure the Kα line and bremsstrahlung x-ray spectral distribution, respectively. Both Kα and 70–200 keV x-ray yields decrease 3- to 5-fold for target backed by the substrate. 2- to 4-fold reduction of Kα and 70–200 keV x-ray yields for the 8.5 μm targets relative to 50 μm targets was observed. Moreover, a significant background x-ray emission generated from the target holder reduces the ratio of signal to noise. Adopting a low-Z material holder can mitigate the x-ray background noises. This study is instructive to optimize target design for the high-intensity laser-driven Kα or continuous x-ray sources.

In this study, experiments and simulations of Ne-like Ge soft X-ray lasers driven by nanosecond fundamental-frequency (1ω) and double-frequency (2ω) lasers are performed. The results show that 2ω lasers are also able to drive and produce Ne-like Ge soft X-ray lasers, even though the requirements for the driving conditions greatly increase compared to 1ω lasers. It is expected that the laser outputs at 23.2 and 23.6 nm will be stronger at higher power densities. The results provide a good foundation for executing experiments using Ne-like Ge soft X-ray lasers at existing large laser facilities, which cannot currently sustain 1ω drive lasers.

In order to verify that the large-scale low-density plasma has a significant gain effect on the quality of the ultra-hot electron beam in ultra-strong ultra-short pulse laser interactions with matter, on the Shenguang-II upgraded laser facility, we carry out an experimental study on the optimization of relativistic electron beams that combine long and short pulse lasers to generate large-scale low-density pre-plasma. A nanosecond laser is used to ablate the thin hydrocarbon film. After a period of time, a large-scale low-density plasma is formed. The second picosecond short pulse laser then interacts with the formed low-density plasma, and accelerates the electrons to the relativity magnitude. Through the comparative analysis between different experimental conditions in the experiment, it is found that the existence of large-scale low-density plasma significantly increases the intensity of the relativistic electron beam along the laser propagation direction. In the comparative test of three shooting methods (long and short pulse combined driving double-layer target, short pulse driving double-layer target, short pulse driving single-layer target), we find that the energy bands above 1 MeV can be produced by the long pulse and the short pulse jointly driving double-layer target. The gamma-ray intensity is nearly twice that of the other two schemes. In addition, we also find in the experiment that when the time interval between nanosecond-picosecond pulses changes, the pre-plasma electron density and density scale length of the CH film irradiated by the nanosecond laser will be different. When the time interval is 0 ns, the expansion of the plasma is still insufficient, and the density distribution of the pre-plasma is steep. Part of the picosecond laser energy will be reflected at the critical density surface. Insufficient absorption of picosecond laser energy reduces the generation of relativistic electrons.When the time interval is 1 ns, the plasma state is more appropriate. The picosecond laser will form a self-focusing plasma channel in the plasma, thereby efficiently depositing energy, breaking through the energy limit of ponderomotive force acceleration, and obtaining more higher energy relativistic electrons. When the time interval is longer, such as 1.5 ns or more, the plasma can be fully expanded, the electron density becoming too low. Most of the picosecond laser will pass through the pre-plasma, affecting energy deposition and failing to generate more relativistic electrons.

Magnetic reconnection, breaking and reorganization of magnetic field topology, is a fundamental process for rapid release of magnetic energy into plasmas that occurs pervasively throughout the universe. In natural circumstances, the plasma properties on either side of the reconnection layer are almost asymmetric, in particular for the collision rates that critically determine the underlying reconnection mechanism. To date, all laboratory experiments on magnetic reconnections have been limited to purely collisional or collisionless regimes. Here, we report a well-designed experimental investigation on magnetic reconnections in a hybrid collisional-collisionless regime by interactions between laser-ablated copper and plastic plasmas. We directly observe the topology evolutions of the whole process of this asymmetric magnetic reconnection by highly-resolved proton radiography. Through this, we show that the growth rate of tearing instability in such a hybrid regime is still extremely large, resulting in rapid formation of multiple plasmoids and generation of plasmoid-dominated current sheet.

In order to verify that, the large-scale low-density plasma has a significant gain effect on the quality of the ultra-hot electron beam in ultra-strong ultra-short pulse laser interactions with matter. On the Shenguang-II Upgraded laser facility, we carried out an experimental study on the optimization of relativistic electron beams that combined long and short pulse lasers to generate large-scale low-density pre-plasma. A nanosecond laser is used to ablate the thin hydrocarbon film. After a period of time, a large-scale low-density plasma is formed. The second picosecond short pulse laser then interacts with the formed low-density plasma, and accelerates the electrons to the relativity magnitude. Through the comparative analysis between different experimental conditions in the experiment, it is found that the existence of large-scale low-density plasma significantly increases the intensity of the relativistic electron beam along the laser propagation direction. In the comparative test of three shooting methods (long and short pulse combined driving double-layer target, short pulse driving double-layer target, short pulse driving single-layer target), we found that the long and short pulse combined driving double-layer target program produced energy bands above 1MeV. The gamma-ray intensity is nearly twice that of the other two schemes. In addition, we also found in the experiment that when the time interval between nanosecond-picosecond pulses changes, the pre-plasma electron density and density scale length of the CH film irradiated by the nanosecond laser will be different. When the time interval is 0ns, the expansion of the plasma is still insufficient, and the density distribution of the pre-plasma is steep. A part of the picosecond laser energy will be reflected at the critical density surface.Insufficient absorption of picosecond laser energy reduces the generation of relativistic electrons.When the time interval is 1ns, the plasma state is more appropriate. The picosecond laser will form a self-focusing plasma channel in the plasma, thereby efficiently depositing energy, breaking the energy limit of ponderomotive force acceleration, and obtaining more higher energy relativistic electrons. When the time interval is longer, such as 1.5ns or more, the plasma has been fully expanded, the electron density is too low. Most of the picosecond laser will pass through the pre-plasma, affecting energy deposition and unable to generate more The relativistic electron.