Thermally tuning terahertz surface plasmon polaritons in corrugated semiconductor films

In this work, we show that surface plasmon polaritons (SPPs) at terahertz (THz) frequencies can be tuned by changing the temperature in a periodically corrugated thin film of indium antimonide (InSb) sandwiched between air and dielectric. When a THz electromagnetic wave illuminates the structure, the temperature-dependent THz SPPs can be excited, and the first and second-order modes and their crosscouplings are observed in the band structure of SPPs. Reflection dips and transmission resonances are observed in those modes. By increasing temperature, transmissions decrease and reflections increase significantly. Our studies indicate that such effects may have potential applications in designing thermally controlled THz devices.