MEMS-Based Terahertz Detectors

Abstract

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 1-5 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 noise equivalent temperature difference (NETD) less than 500 mK and a refresh rate of 30Hz. OverviewTHz radiation covers the part of the electro-magnetic (EM) spectrum between the microwaves and infrared (IR), which corresponds to frequencies from 100GHz to 10THz [1]. It has attractive properties, which make it suitable for various applications such as spectroscopy, sensing and imaging [2][3][4]. THz radiation has non-ionizing nature, since THz photons do not carry sufficient energy to ionize an electron from an atom or molecule. Therefore, it does not cause any significant damage to human DNA, as do X-ray imaging techniques.

Reconfigurable THz Metamaterial Filter Based on Binary Response for Information Processing System

“…Moreover, many studies reported numerous microelectro-mechanical-system (MEMS) based metamaterial and metasurface structures for numerous applications [18][19][20][21][22]. Ma et al [18] developed polarization-sensitive MEMS-based tunable metamaterials for the terahertz spectrum.…”

“…At 480 GHz, the system manifested a high contrast switching efficiency of 16.5 dB. Meanwhile, Bilgin et al [20] developed a MEMS-based THz detector which was characterized to extract its mechanical performance in 2015. The detector had a pixel size of 200 × 200 µm, working between 1 and 5 THz bands.…”