Electromagnetically Induced Transparency Active Switch Control Based On Indium Antimonide (InSb)

Electromagnetically induced transparency(EIT)is an interference effect in a three-level atomic system.Because the excited atoms in different transition paths produce quantum interference cancellation,the light absorption at the resonance frequency is reduced and even becomes transparent.The EIT phenomenon based on the quantum system is difficult to realize because of the harsh experimental conditions in the quantum system.The ability of natural materials to control terahertz waves is very limited due to their atomic type and structural limitations.The emergence of metamaterials with extraordinary physical properties and artificially designed structures has attracted wide attention from researchers.Based on the powerful electromagnetic control capabilities of metamaterials,it has become a reality to use metamaterials to realize the EIT phenomenon in quantum systems.Using metamaterials to achieve the EIT effect not only avoids the harsh experimental conditions in the quantum system but also has outstanding advantages and practical significance in the field of slow-light devices and optical storage devices.In this paper,using the excellent temperature-sensitive characteristics of indium antimonide(InSb),the main research is EIT active switch control based on InSb.The specific work content is as follows:(1)We propose a periodic "F"-shaped EIT structure composed of one vertical InSb bar and two horizontal InSb bars.By increasing the distance between the two horizontal InSb bars and the distance between the vertical InSb bar and the horizontal InSb bars,the results show that the transmission amplitude of the EIT window is modulated from on to off.Meantime,when the external temperature rises from 300 K to 350 K,due to the temperature-sensitive characteristics of InSb,the center frequency of the EIT window gradually shifts to high frequency.The active tuning of the center frequency of the EIT window is realized.(2)We propose a thermally controlled EIT metamaterial structure.The structure consists of a vertical metal bar and two split rings.InSb is located in the opening of the split rings.When the external temperature rises from 240 K to 320 K,the EIT window undergoes switching modulation,and the modulation depth reaches 86.8%.Change the cell structure,when the external temperature rises from 200 K to 240 K,the EIT window undergoes switching modulation,and the modulation depth reaches 77.7%.The coupled harmonic oscillator model is used to fit the simulation results,and the fitting results are in good agreement with the simulation results.(3)We propose an EIT metamaterial structure that is polarization insensitive and can be actively controlled by magnetic field and temperature.The transmission spectrum in the x and y polarization directions is simulated when the temperature is 300 K,the results show that the transmission spectrum is the same,so the metamaterial has polarization insensitivity.The transmission spectrum of the external magnetic field in the z,x,and y directions at a temperature of 300 K is studied.The magnetic field strength gradually increases from 0.1T to 0.7T.When the direction of the external magnetic field is consistent with the polarization direction,the increase in magnetic field strength will not affect the transmission spectrum of the metamaterial.When the direction of the external magnetic field is perpendicular to the polarization direction,the increase in magnetic field strength will cause a redshift of the resonance frequency.The direction and strength of the external magnetic field are fixed.When the external temperature gradually increases from 280 K to310K,the center frequency of the EIT window will blue shift.