Analytical Modeling and Design of a Graphene Metasurface Sensor for Thermo-Optical Detection of Terahertz Plasmons
Abbas Hamouleh-Alipour, Ali Mir, Ali Farmani
Abstract
Thermo-optic mechanism for plasmonics sensing of terahertz radiations is numerically and analytically investigated for metasurface formed from Graphene/SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and simulated at room temperature. For this purpose, here, by considering coupling condition as well as strong light-matter interaction in graphene metasurface a very compact footprint in less than half of the wavelength is proposed. Also, for deep benchmark of structure at different temperature, tunable optical properties of graphene is considered. Subsequently, the numerical operation of the sensor fulfilled based 3-dimension finite-difference time-domain (3D-FDTD) and also, the transfer matrix method (TMM) modelling is introduced. In order to investigate the relationship between the temperature variation and tunable behavior of the structure on the performance parameters, temperature is increased from 0 to 600 K in steps of 300, whereas the other parameters were fixed. Numerical results show that the max sensitivity and figure of merit (FoM) are more than 1140 nm/RIU and 5.1, respectively. Then, we numerically simulate the optical cross-section including absorption, scattering and total of them. Also, by harnessing of graphene's surface conductivity properties, we indicate the giant tunability and minimum transmittance of % 0.02 in frequency of 14 THz in which the best track of optical performance over a wide range of frequency is occurred. Eventually, a novel research direction of the software-defined metasurface is explained, which is tried to achieve the graphene-based metasurface toward unique in controllability and harnessing of the light. This proposed thermo-optical metasurface structure can be used as a nanosensor for exciting surface plasmons.