Metamaterial based terahertz detector

We present a metamaterial based terahertz (THz) detector. The detector design, which combines metamaterials and MEMs, is frequency selective, and we have fabricated and tested detectors at 95 GHz and 693 GHz with noise equivalent powers of 1.13 × 10⁻⁸ W/√Hz and 2.96 × 10⁻⁸ W/√Hz and responsivities of 16,500 V/W and 6,800 V/W, respectively. These values were achieved at room temperature and pressure.

1. Introduction

Though progress in THz detector sensitivity over the past quarter century has been impressive, it is mostly accredited to improvements in thermometer sensitivity. Inefficient absorption of THz radiation which yields a low heat-induced temperature variation remains the performance bottleneck. Furthermore, most THz microbolometers show broadband response, which can be undesirable for applications such as spectroscopic detection of materials with unique THz responses. Here we present a THz detector based on metamaterial resonators. These metamaterials show high absorption, and their sub wavelength nature enables their use as a focal plane array (FP A) to image near the diffraction limit. Furthermore, their narrow band resonance is a salient feature for spectrally selective detection applications. Consequently, metamaterials hold great promise for facilitating the development of a “versatile” THz detector which can a) strongly absorb THz radiation; b) operate at room temperature with decent responsivity and sensitivity; c) be scaled up to function as a multi-pixel array for imaging applications; d) operate selectively at any frequency in the THz regime; and e) be lightweight and low cost.