Plasmonic Metasurfaces for Controlling the Spectrum of Terahertz Radiation Sources

Abstract

We report on the development and fabrication of a plasmonic metasurfaces for PCA based on InAlAs/InGaAs superlattice heterostructures. As a result of THz time-domain measurements, it was found that for PCA emitters with a 150 nm thick plasmonic metasurface, the maximum recorded overall THz power was 5.3 (the optical-THz conversion efficiency was 0.19 %) under laser pumping with an average power of 2.8 mW and a bias voltage of 8.6 V. The increase in the signal-to-noise ratio due to the excitation of plasmon modes exceeds ~80 dB. The experiments have shown that the increase of metallization thickness provides the increase of the emitted power. The results could open a pathway towards the development of the Russian THz spec-troscopic and imaging systems.