强场飞秒激光作用于原子时，原子中的电子除了发生多光子电离、隧穿电离等过程外，还有很大的概率处于高激发态。这种高激发态的原子在超强超短激光场中非常稳定，并且与强场中的其它许多现象密切相关，例如，中性粒子加速、多光子拉比振荡、近阈值谐波辐射等，因此近十几年来是强场超快物理领域的研究热点之一。在这些研究中，强激光场中里德堡原子的产生机制、激光对里德堡态的调控、里德堡态强场电离及稳定性等，是关注的主要问题。本文将概述强激光驱动的里德堡态的产生机制，包括多光子共振激发，受挫隧穿电离等。重点介绍强激光场驱动的里德堡态原子激发过程中的多种干涉现象。这些干涉现象提供了里德堡原子强场激发的动态过程信息。同时，还将介绍激发态原子在强激光场中的电离过程，特别是圆偏光驱动的里德堡原子电离的圆二色性。

The anisotropic properties and applications of β-gallium oxide (β-Ga₂O₃) are comprehensively reviewed. All the anisotropic properties are essentially resulted from the anisotropic crystal structure. The process flow of how to exfoliate nanoflakes from bulk material is introduced. Anisotropic optical properties, including optical bandgap, Raman and photoluminescence characters are comprehensively reviewed. Three measurement configurations of angle-resolved polarized Raman spectra (ARPRS) are reviewed, with Raman intensity formulas calculated with Raman tensor elements. The method to obtain the Raman tensor elements of phonon modes through experimental fitting is also introduced. In addition, the anisotropy in electron mobility and affinity are discussed. The applications, especially polarization photodetectors, based on β-Ga₂O₃ were summarized comprehensively. Three kinds of polarization detection mechanisms based on material dichroism, 1D morphology and metal-grids are discussed in-depth. This review paper provides a framework for anisotropic optical and electric properties of β-Ga₂O₃, as well as the applications based on these characters, and is expected to lead to a wider discussion on this topic.

研究了一维双链钙钛矿材料C₅H₁₆N₂Pb₂I₆的光学各向异性。采用水相法合成了一维双链钙钛矿C₅H₁₆N₂Pb₂I₆晶体，采用光谱对其进行表征，其荧光发射的线性二色比可达17.4，高于已报道的一维单链C₄H₁₄N₂PbI₄钙钛矿。表明降低晶体的对称性可用于提高光学各向异性。进一步通过Kramers-Kronig关系获得钙钛矿的复介电常数及其双折射和二色性，其中二色性和双折射分别达到了1.5和1.3。

The chiral feature of an optical field can be evaluated by the parameter of g-factor enhancement, which is helpful to enhance chiroptic signals from a chiral dipole. In this work, the superchiral spot has been theoretically proposed in metal-insulator-metal waveguides. The g-factor enhancement of the superchiral spot can be enhanced by 67-fold more than that of circularly polarized light, and the spot is confined in the deep wavelength scale along each spatial dimension. Moreover, the position of the superchiral spot can be tuned by manipulating the incident field. The tunable superchiral spot may find applications in chiral imaging and sensing.

本文提出了一种基于相变材料Ge₂Sb₂Te₅ (GST)的圆二色性可调谐外在手征超表面，该超表面由两层对称的银(Ag)方形开口谐振环和GST中间层单元周期排列而成。结合斜入射光线，该超表面能实现与手征结构相同的电磁特性。数值模拟结果表明：该超表面在50 THz~300 THz的频率范围内，GST为非晶态时，圆二色性(CD)值最大为0.85；GST为晶态时，CD值最大为0.52。当GST在两种相态(非晶态-晶态)之间切换时，实现了70 THz左右的频率调谐。通过研究电场分布，解释了圆二色性产生的原因；还研究了入射角和结构参数对该超表面圆二色性的影响。这项研究在光频段高效偏振调制器件、圆偏振器和偏振滤光器等方面有潜在的应用价值。

作为生物体的本质属性，物质的手性表征在生理学和药理学领域有着重要的意义。当电磁波与手性材料作用时，会出现旋光效应、圆二色性和手性光力等特殊的光学活性现象，并成为材料手性检测的强大工具。由于手性分子的结构远小于激发光的波长，因此分子自身的手性光学效应通常很弱，极大限制了检测技术的精度。近年来，纳米光子技术的进步有望增强纳米尺度下光与物质之间原本很弱的手性光学效应，使得手性的高灵敏度、高分辨率检测成为可能。回顾了手性光学的发展及其在生物分子检测等方面的应用，讨论了基于等离子耦合圆二色性和超手性近场在圆二色性增强方面的策略，介绍了基于横向手性光力的物质构型分选和基于结构光场光力效应的手性结构表征方法，并对该领域未来进一步的发展进行了展望。