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构建了结构为石墨烯/光学隔离层/银基底的光学微腔来提高石墨烯的光吸收效率。理论研究表明,通过合理设置光学微腔中光学隔离层的厚度,在正入射条件下,石墨烯的吸收光谱出现吸收峰而且最大光吸收效率可达8.5%,约为空气中单层石墨烯光吸收效率(约2.3%)的3.7倍。同时,研究结果还表明,可以通过改变光学隔离层的厚度来调控吸收峰的位置和半高宽。在斜入射条件下,石墨烯对横电波(光电场方向垂直于入射面)入射光的光吸收效率可达42%,约为空气中单层石墨烯光吸收效率的18.3倍。计算结果对石墨烯光电探测器的制备及应用具有一定的指导意义。
An optical microcavity with a structure of graphene / optical isolation layer / silver substrate was constructed to improve the light absorption efficiency of graphene. Theoretical studies show that the absorption peak of graphene under normal incident conditions can be achieved by setting the thickness of the optical isolation layer in the optical microcavity reasonably and the maximum light absorption efficiency can reach 8.5%, which is about the monolayer graphene light in air 3.7 times the absorption efficiency (about 2.3%). At the same time, the research results also show that the position and FWHM of the absorption peak can be adjusted by changing the thickness of the optical isolation layer. Under oblique incident conditions, the light absorption efficiency of graphene to incident light in the transverse electric field (the direction perpendicular to the incident plane of the photoelectric field) is up to 42%, which is about 18.3 times of the light absorption efficiency of monolayer graphene in air. The calculation results have certain guiding significance for the preparation and application of graphene photodetectors.