光控电磁超表面太赫兹调制器的研究

Photo-Excited Terahertz Modulator Based on Electromagnetic Metasurface

本论文利用光敏硅的可变电导率特性,设计了一种基于光控的电磁超表面宽带太赫兹调制器.电磁超表面由金属薄膜、隔离层以及具有光敏硅的特殊结构组成.光敏硅的电导率从1 S/m变为2×105S/m时,谐振频率从1.4 THz变到1.0 THz,其反射率从-5 d B变到-38d B,频移为0.3 THz,振幅调制深度接近100%,并且电磁超表面的反射率小于-10 d B的带宽从0变为0.64 THz,实现宽频带低反射主要与相邻结构单元的反射相位差有关系.该电磁超表面结构为大范围、宽频带的太赫兹调制器提供了一种新的思路和途径,将在通信、国防、成像等方面有重要的应用前景.

We designed a photo-excited broadband terahertz modulation based on electromagnetic metasurface using the tunable conductivity photosensitive silicon.The metasurface consists of a special structure with hybrid photosensitive silicon and a metallic ground plane that are separated by a dielectric spacer.The resonance frequency can be varied from 1.4 THz to 1.0THz when the silicon conductivity ranges from 1 S / m to 2 × 105 S / m,and the reflectivity varies from-5 d B to-38 d B.The frequency shift is 0.3 THz,and the amplitude modulation depth reaches almost 100 % at the resonance frequency.Aband width of reflectivity less than 10 d B for the metasurface is achieved from 0 to 0.64 THz,and the result related to the reflection phase difference of adjacent structure units.The metasurface provide a new approach to achieved wide bandwidth and range terahertz modulation and have the numerous potential applications in the development of broadband communication,military radar,medical image and so on.