随机电磁光场传输中的偏振涨落特性研究

As a degree of freedom for manipulation of light fields, the state of polarization has shown great potential in light manipulation which has progressed a lot in spatial non-uniform modulation and has become a research hotspot in optics. From another angle, this project focuses on the changes in polarization state over time, named polarization fluctuations. The polarization fluctuations have been developed as carriers of information encoding as well as channels of information about light sources and propagation media. They are of great importance to applications in many fields, such as optical communication, polarimetric radar imaging, supercontinuum generation, semiconductor laser, and so on. Based on the recently defined polarization correlation functions, the polarization fluctuations of random electromagnetic fields with several special forms have been studied. To discover the changes in polarization fluctuations during light-matter interaction, we will carry out the project about the polarization fluctuations of stochastic electromagnetic light fields during propagation. In this project, the polarization fluctuations of two-dimension random electromagnetic fields with multiple forms upon propagation in optical systems and random media will be considered, and the modulations of the polarization fluctuations by the source parameters and the media parameters are to be discussed. Furthermore, we will focus on the changes in the polarization fluctuations in the transformation from two-dimension fields into three-dimension fields through optical systems, and the effective method to modulate the polarization fluctuations of three-dimension light fields is to be explored. This project will contribute to the electromagnetic theory in coherence optics, and will provide new insight into the application of polarization state in light manipulation and optical communication.

偏振态作为光场调控的一个自由度，其空间非均匀调制技术已取得很大进展，成为光学领域的一个研究热点。本项目从另一个角度出发，考虑偏振态随时间的变化即偏振态涨落。偏振涨落可作为信息编码的载体以及光源和传输介质的信息渠道，在光通讯、偏振雷达成像、超连续谱产生、半导体激光等领域具有重要的应用价值。根据最近定义的偏振关联函数，几例特殊随机电磁光场的偏振涨落特性得以揭晓。鉴于目前光与物质相互作用时偏振涨落特性的变化尚不明确，本项目拟研究随机电磁光场传输中的偏振涨落特性。主要包括：研究多种形式的二维随机电磁光场在光学系统和随机介质中的偏振涨落，探究光源参数和介质参数对偏振涨落特性的调控作用；研究二维光场经光学系统变换成三维光场的偏振涨落变化，探索对三维光场偏振涨落特性调控的有效方法。本项目将丰富和发展相干光学电磁理论，为偏振态在光场调控、光通讯等领域的应用提供新视角。

随着纳米光学和复杂结构光场的快速发展，三维偏振特性的研究成为迫切需求。本项目针对随机电磁光场的三维偏振特性开展研究，构建随机光场的空间-时间偏振关联函数，并研究光学隧道效应和二维到三维光学变换中的三维偏振态。取得的主要研究成果如下：（1）构建二维和三维随机电磁光场的空间-时间偏振关联函数，揭示高斯统计随机光场的偏振关联函数与电磁相干度等可测量物理量之间的关系，并呈现腔内黑体辐射场和远场黑体辐射的空间-时间偏振关联特性，以及温度对该特性的影响。（2）揭示光学隧道效应中的三维偏振态特性，得到倏逝波光场的偏振态结构、偏振态中的识别成分以及偏振态的不规则度，并呈现入射角和棱镜间距对倏逝波偏振性质的调控。进一步讨论由二维光场产生三维光场的一般情形，并揭示一般情形下三维光场的识别成分和一个本征态仅取决于光学系统的事实。（3）提出采用双纳米粒子探测三维随机电磁光场相干性的方法，为三维空间-时间偏振关联特性的测量提供可能。研究成果为三维偏振特性提供新认识，将有助于推动三维偏振在近场光学、纳米光学、大数值孔径成像、半导体激光、偏振雷达成像等领域的应用和发展。