A MEMS-based terahertz detector with metamaterial-based absorber and optical interferometric readout

A MEMS based novel THz detector structure is designed and realized by micro fabrication. The detector is then characterized to extract its mechanical performance. Operating in 0.5-2 THz band, the detector has a pixel size of 200 μm × 200 μm. Bimaterial suspension legs consist of Parylene-C and titanium, the pair of which provides a high mismatch in coefficients of thermal expansion. The pixel is a suspended Parylene-C structure having a 200 nm-thick titanium metallization. Operation principle relies on conversion of absorbed THz radiation into heat energy on the pixel. This increases the temperature of the free-standing microstructure that is thermally isolated from the substrate. The increase in temperature induces mechanical deflection due to bimaterial springs. The detector is designed to deliver a detectivity (D*) of 2 × 109 cm Hz−1/2/W and a refresh rate of 20 Hz.