Efficient Terahertz Detection with Perfectly-Absorbing Metasurface

We demonstrate a unique photoconductive design for terahertz (THz) detection based on a perfectly absorbing, all-dielectric metasurface. Our design exploits Mie resonances in electrically connected cubic resonators fabricated in low-temperature grown (LT) GaAs. Experimentally, the detector achieves very high contrast between ON/OFF conductivity states (10
⁷
) whilst also requiring extremely low optical power for optimal operation (100 $\mu$W). We find that the Mie resonances dissipate sufficiently fast and maintain the detection bandwidth up to 3 THz.