Comparison of Thermal Detector Arrays for Off-Axis THz Holography and Real-Time THz Imaging

Abstract

In terahertz (THz) materials science, imaging by scanning prevails when low power THz sources are used. However, the application of array detectors operating with high power THz sources is increasingly reported. We compare the imaging properties of four different array detectors that are able to record THz radiation directly. Two micro-bolometer arrays are designed for infrared imaging in the 8–14 μm wavelength range, but are based on different absorber materials (i) vanadium oxide; (ii) amorphous silicon; (iii) a micro-bolometer array optimized for recording THz radiation based on silicon nitride; and (iv) a pyroelectric array detector for THz beam profile measurements. THz wavelengths of 96.5 μm, 118.8 μm, and 393.6 μm from a powerful far infrared laser were used to assess the technical performance in terms of signal to noise ratio, detector response and detectivity. The usefulness of the detectors for beam profiling and digital holography is assessed. Finally, the potential and limitation for real-time digital holography are discussed.

Topography of hidden objects using THz digital holography with multi-beam interferences

“…Interferometric signals were recorded with an uncooled microbolometer array based on amorphous silicon featuring 480 × 640 pixels on a 17 μm pixel pitch (Gobi-640-GigE, Xenics, Leuven, Belgium). Although it was designed for infrared radiation between 8 and 14 μm, it was shown to work at THz wavelengths and to have better lateral resolution than currently available dedicated THz bolometers and pyroelectric detectors [26].…”

Non-Contact, Non-Destructive Testing in Various Industrial Sectors with Terahertz Technology

“…Other array elements such as pyroelectric crystals [89][90][91], microelectromechanical systems (MEMS) [92], and superconducting films [93] have also been reported. Pyroelectric crystals have limited sensitivity due to the relatively large pixel size, while MEMS have shown incredible response speed in the kHz range.…”

An Optically Tunable THz Modulator Based on Nanostructures of Silicon Substrates

“…Terahertz (THz) radiation (0.1~10 THz) triggers a great number of intriguing and complex physical, biological, and chemical phenomena. It consequently possesses wide practical application prospects in communications, spectroscopy, and imaging [1][2][3][4][5][6][7]. For THz imaging purposes, a THz spatial light modulator (SLM) is involved, which requires the THz modulator to be fast and efficient.…”