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

• Published in: Sensors and actuators. A. Physical. 2016-06, Vol.244, p.292-298
• Main Authors: Bilgin, Habib, Zahertar, Shahrzad, Sadeghzadeh, Seyedehayda, Yalcinkaya, Arda D., Torun, Hamdi
• Format: Article
• Language: English
• Subjects: Actuators; Conversion; Deflection; Detectors; Legs; Mechanical properties; MEMS; Metamaterials; Microfabrication; Optical readout; Pixels; Terahertz technology; Titanium
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2016.04.021

•We developed a novel MEMS-based terahertz detector with metamaterial-based absorbers.•We fabricated the detectors made of Parylene and titanium using microfabrication techniques.•We characterized the absorption characteristics of the metamaterials using a terahertz timedomain spectroscope.•We implemented a diffraction grating interferometer at pixel level for the detectors and present the experimental characteristics of the readout method. 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 0.5–2THz band, the detector has a pixel size of 200μm×200μm. 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 2×109cmHz−1/2/W and a refresh rate of 20Hz.