Two-dimensional full-Stokes polarization imaging element and preparation method thereof

Abstract

A two-dimensional full-Stokes polarization imaging element belongs to an optical device, and can be used for realizing real-time polarization imaging. The element is composed of a light-transmitting substrate and a rotational symmetric medium structure layer located on the light-transmitting substrate. The medium structure layer is composed of four linear gratings with different orientations and two symmetrical structure arrays with different rotation directions. The element can be manufactured through the electron beam exposure and development technology, the ion beam etching technology and other technological processes. The full-Stokes polarization imaging element is excellent in performance, in the band of 1.54 microns, the transmittance of linear polarized light can exceed 92.5%, and the extinction ratio reaches 33.57 db; and the circular polarization dichroism exceeds 92%. For circularly polarized light, the polarization transmittance is greater than 95%, the circular polarization dichroism reaches 94.3%, and the extinction ratio is greater than 45: 1. Meanwhile, the structure is simple, the performance is excellent, manufacturing is easy, and the high application value is achieved in the fields of optical sensing, optical imaging and the like.

Description

technical field [0001] 本发明涉及偏振光学元件,具体涉及一种全斯托克斯偏振成像元件及其制备方法。 Background technique [0002] 偏振成像技术是光学领域的一种新技术,光的偏振特性能够提供目标的光强图像无法显示的表面粗糙度、纹理走向、表面取向、表面电导率、材料理化特征、含水量等特征,对物体轮廓和表面去向识别具有明显的优越性,偏振成像技术在大气、自然地物、人工目标、医学诊断以及天文学探测领域具有广泛应用。例如:对隐藏或伪装目标探测;对不同物质检测;模糊轮廓(指纹、碑文等)识别;烟雾环境去雾成像;进行癌症、烧伤等医学诊断;用于星载或机载遥感等。偏振成像技术与现有的成像系统相比,增加了对光线的各个偏振分量进行测量,然后的得到Stokes矢量图或Mueller图,进而进行分析计算得到更多的特征信息。 [0003] 偏振成像技术中,重要的步骤是获取不同偏振方向的信息。现有的焦平面偏振相机通过ccd相机的像素做一层偏振器件,可以同时获得物体不同偏振方向上的偏振信息,实现实时偏振成像,但是现存的相机仅能够探测线偏振矢量,无法对圆偏振分量进行有效的探测。在偏振光成像中,圆偏振光在大颗粒散射介质中具有独特的优势,如在水底、烟雾、云层以及生物组织中圆偏振光的成像质量要优于线偏振光。因此增加对圆偏振光的获取可以提高雾霾、云雾等恶劣天气环境中的穿透性。 [0004] 随着含表面等离子波的亚波长结构器件与技术的发展,许多课题组在利用纳米微结构区分左右旋圆偏振光方面做了大量的研究工作。例如公开号为CN101852884B和CN101782666B专利文献通过在介质基地上放置周期性的双螺旋状和螺旋状金属线来实现对左旋和右旋圆偏振光的选择性透过。这些圆偏振检测单元结构为复杂的三维结构,工艺复杂,成本昂贵,并且消光比小透过率低。 Contents of the invention [0005] 本发明为一种二维全斯托克斯偏振成像元件,可以实现实时偏振成像,并且性能优良,透过率高、加工简单,制备工艺成熟,适合批量加工制备,具有很高的商业化应用 prospect. In order to achieve the above-mentioned purpose of the invention, the techni...

AI Technical Summary

Problems solved by technology

The structure of these circular polarization detection units is a complex three-dimensional structure, the process is complicated, the cost is expensive, and the extinction ratio is small and the transmittance is low.

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