Metamaterial-based terahertz converter

Since the early 1980s the terahertz range (0.1 to 10 THz) attracts permanent attention of fundamental and applied science. Due to its unique properties terahertz radiation is used in a wide range of applications such as spectroscopy, non-destructive defectoscopy and security systems. The design of high-efficiency terahertz absorbers and converters is currently the main task in the development of terahertz technologies. In this work a frequency selective high-Q metamaterial is used for the fabrication of a terahertz-to-infrared converter. The converter consists of a metamaterial-based terahertz absorber coated with a micrometer-thick graphite layer that reemits the absorbed energy in the infrared range. We have carried out electrodynamic and the related thermodynamic calculations of the suggested radiation converter. Numerical simulations yield an electromagnetic radiation absorption coefficient of 99.998% and an analytically calculated converter efficiency of 93.8%. Thanks to these advanced parameters suggested terahertz converter can find it's applications in a wide range of transportation security inspection and defectoscopy tasks.