Compact terahertz spectrometer based on a metasurface

We design, fabricate, and measure a novel spectrometer based on meta-surface structures, aiming to optimize its spectroscopic resolution within a band from 1.7 to 2.5 THz. The latter corresponds to a bandwidth of 38%, being comparable with a grating spectrometer. The meta-surfaces apply unit cells that consist of double-anchor structures based on gold, polyimide and gold triple layers. Several quantum cascade lasers that operate at slightly different frequencies around 2.1 THz were used to validate the spectrometer. We have measured a resolving power R of 273 and an efficiency of 78 %. Our results demonstrate for the first time a centimeter-sized, light weight FIR spectrometer with a promising resolution, which has potential to replace the half meter-sized, heavy grating based spectrometers in this wavelength band.