Rainbow trapping and releasing in InSb graded subwavelength grooves by thermal tuning at the terahertz range

Research in terahertz (THz) science and technology has been booming in view of its potential application in a variety of light-matter interaction areas. Intrinsic indium antimonide (InSb) is an excellent tunable candidate material that supports surface plasmon polaritons (SPPs) in the THz range. In this paper, we present calculations to demonstrate the feasibility of exciting SPPs using an InSb graded grating structure. The InSb structure exhibits an extraordinary property of trapping and releasing electromagnetic waves in terahertz regimes (0.084-0.326 THz). With a fixed frequency, the electric field magnitude distributions of the gradient InSb grating waveguide at different temperatures are compared; these show that the InSb grating structure is an excellent candidate for trapping and releasing SPPs in the THz range. The thermo-optic property of InSb permits the meaningful application for compact low-frequency surface-plasmon optical devices in the future. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.