THz IMAGING SYSTEM BASED ON THz-to-IR CONVERTER

摘要

The simple and flexible bolometric system for THz imaging employing the scheme of terahertz-to-IR conversion is described. In the proposed scheme the terahertz waves are absorbed by high-performance ultra-thin THz absorbers which thermal heating is detected by a conventional IR camera. The absorbers are implemented on basis of artificial impedance surfaces (AIS) with thickness l/50th-l/40th of the operating free-space wavelength, which are designed for close to unity absorptivity in the range 0.3-0.4 THz at high spectral and polarization resolution. The general strategy for realizing ultrathin AIS-absorbers applicable to selective bolometric devices is considered. The proposed approach is tested in experiments on real-time THz imaging using a backward-wave THz oscillator with 3-10 mW output radiation power.