Electrically tunable metasurface by using InAs in a metal–insulator–metal configuration

Nanophotonics

Sorger Volker J.¹  Park Junghyun²  Kim Soo Jin³  Kim Seong Jun³ 

[1] Department of Electrical and Computer Engineering, George Washington University, Science & Engineering Hall, 800 21st Street, NW, ​Washington DC20052, USA;Samsung Advanced Institute of Technology, Samsungro 130, Youngtong-gu, Suwon16678, Republic of Korea;School of Electrical Engineering, Korea University, Engineering Building Room 216,145, Anam-ro, Seongbuk-gu, Seoul02841, Republic of Korea;

关键词: inas;    metasurface;    optical modulator;    surface plasmonics;    wavefront shaping;   

DOI  :  10.1515/nanoph-2021-0618

来源: DOAJ

【 摘 要 】

The ability of modulating optical properties at a lateral subwavelength scale is of crucial importance due to its potential applications for wide-angle holographic displays, optical communications, and interferometric sensors. Here, we present an electrically tunable metasurface whose optical properties can be element-wise controlled at the lateral subwavelength scale in the mid-infrared wavelength regime. Our proposed device facilitates an n-doped InAs layer as a dynamic-tunable layer, and the charge carrier concentration inside the InAs layer is tailored by external gate biases. This InAs active layer is sandwiched between top aluminum strip antennas and a bottom gold substrate, forming the metal–insulator–metal configuration. The change of the charge carrier concentration gives rise to modulation of the amplitude and phase of reflected light in a mid-infrared regime. Numerical investigations show the reflectivity contrast of 44%P with biases of −2.5–0 V and the phase change of 236° with biases of −15 V to +15 V at the wavelength of ∼5 μm. Versatile wavefront shaping such as beam focusing with Fresnel Zone plate and beam steering with saw-tooth phase grating is also provided.

【 授权许可】

Unknown