飞秒磁场脉冲对研究超快磁化、超快退磁、超快磁存储和自旋超快动力学等过程具有重要意义。传统的脉冲磁场受限于脉冲电源性能无法获得毫秒量级以下的超短脉冲磁场，无法研究飞秒尺度的磁动力学过程。利用超短脉冲激光驱动等离子体产生旋转电流是目前产生飞秒磁场脉冲的有效方法。本文利用质点网格法模拟圆偏振拉盖尔高斯光束驱动等离子体中的电子运动从而产生光电流以及飞秒磁脉冲的过程，模拟产生了特斯拉量级的飞秒超短磁脉冲，并系统讨论了驱动激光强度与等离子体密度对磁脉冲的影响。结果表明，脉冲磁场的脉宽与驱动光一致，其强度随着激光场强度、等离子体密度增加而增加。通过本文研究寻找产生飞秒磁脉冲的优化实验参数，有望将超快磁动力学研究推进到飞秒时间尺度。

Bioaerosols exhibit significant broadband extinction performance and have vital impacts on climate change, optical detection, communication, disease transmission, and the development of optical attenuation materials. Microbial spores and microbial hyphae represent two primary forms of bioaerosol particles. However, a comprehensive investigation and comparison of their optical properties have not been conducted yet. In this paper, the spectra of spores and hyphae were tested, and the absorption peaks, component contents, and protein structural differences were compared. Accurate structural models were established, and the optical attenuation parameters were calculated. Aerosol chamber experiments were conducted to verify the optical attenuation performance of microbial spores and hyphae in the mid-infrared and far-infrared spectral bands. Results demonstrate that selecting spores and hyphae can significantly reduce the average transmittance from 21.2% to 6.4% in the mid-infrared band and from 31.3% to 19.6% in the far-infrared band within three minutes. The conclusions have significant implications for the selection of high-performance microbial optical attenuation materials as well as for the rapid detection of bioaerosol types in research on climate change and the spread of pathogenic aerosols.

液晶显示领域中的一个重要研究方向是液晶电光性能的改善。近年来，液晶-纳米科学见证了纳米掺杂增强液晶电光性质的范式转变。一方面，纳米颗粒具备特殊的理化性质能有效改善分散基质的性质；此外，纳米掺杂的液晶复合体系制备工艺简单、电光特性卓越，在显示领域占据重要地位。利用液晶与纳米颗粒间的不同相互作用，研究人员设计了一系列具有高稳定性、低成本、可调谐和可持续的电光器件。然而，纳米颗粒的掺杂有可能造成结构缺陷，不利于液晶的稳定。因此，纳米颗粒的选择是影响液晶电光性能的关键。本文概述了液晶-纳米复合体系的电光特性，着重讨论了纳米颗粒与液晶分子间可能存在的相互作用。同时，综述纳米颗粒掺杂液晶的研究现状，根据纳米颗粒类型总结了纳米掺杂对液晶电光性能的影响，并在此基础上，对未来液晶显示技术与纳米技术的结合进行了展望。

The optimum parameters for the generation of synchrotron radiation in ultraintense laser pulse interactions with planar foils are investigated with the application of Bayesian optimization, via Gaussian process regression, to 2D particle-in-cell simulations. Individual properties of the synchrotron emission, such as the yield, are maximized, and simultaneous mitigation of bremsstrahlung emission is achieved with multi-variate objective functions. The angle-of-incidence of the laser pulse onto the target is shown to strongly influence the synchrotron yield and angular profile, with oblique incidence producing the optimal results. This is further explored in 3D simulations, in which additional control of the spatial profile of synchrotron emission is demonstrated by varying the polarization of the laser light. The results demonstrate the utility of applying a machine learning-based optimization approach and provide new insights into the physics of radiation generation in laser–foil interactions, which will inform the design of experiments in the quantum electrodynamics (QED)-plasma regime.

A machine learning model was created to predict the electron spectrum generated by a GeV-class laser wakefield accelerator. The model was constructed from variational convolutional neural networks, which mapped the results of secondary laser and plasma diagnostics to the generated electron spectrum. An ensemble of trained networks was used to predict the electron spectrum and to provide an estimation of the uncertainty of that prediction. It is anticipated that this approach will be useful for inferring the electron spectrum prior to undergoing any process that can alter or destroy the beam. In addition, the model provides insight into the scaling of electron beam properties due to stochastic fluctuations in the laser energy and plasma electron density.

The emerging two-dimensional materials, particularly transition metal dichalcogenides (TMDs), are known to exhibit valley degree of freedom with long valley lifetime, which hold great promises in the implementation of valleytronic devices. Especially, light–valley interactions have attracted attentions in these systems, as the electrical generation of valley magnetization can be readily achieved — a rather different route toward magnetoelectric (ME) effect as compared to that from conventional electron spins. However, so far, the moiré patterns constructed with twisted bilayer TMDs remain largely unexplored in regard of their valley spin polarizations, even though the symmetry might be distinct from the AB stacked bilayer TMDs. Here, we study the valley Hall effect (VHE) in 40°-twisted chemical vapor deposition (CVD) grown WS₂ moiré transistors, using optical Kerr rotation measurements at 20 K. We observe a clear gate tunable spatial distribution of the valley carrier imbalance induced by the VHE when a current is exerted in the system.The emerging two-dimensional materials, particularly transition metal dichalcogenides (TMDs), are known to exhibit valley degree of freedom with long valley lifetime, which hold great promises in the implementation of valleytronic devices. Especially, light–valley interactions have attracted attentions in these systems, as the electrical generation of valley magnetization can be readily achieved — a rather different route toward magnetoelectric (ME) effect as compared to that from conventional electron spins. However, so far, the moiré patterns constructed with twisted bilayer TMDs remain largely unexplored in regard of their valley spin polarizations, even though the symmetry might be distinct from the AB stacked bilayer TMDs. Here, we study the valley Hall effect (VHE) in 40°-twisted chemical vapor deposition (CVD) grown WS₂ moiré transistors, using optical Kerr rotation measurements at 20 K. We observe a clear gate tunable spatial distribution of the valley carrier imbalance induced by the VHE when a current is exerted in the system.