Research on bi-material MEMS detector arrays for THz imaging

Terahertz (THz) technology has huge potential in detection of concealed objects as well as in medical imaging for non-invasive diagnostics. Recently thanks to improvement of THz sources and detectors, the THz imaging technology has become the hotspot. This paper presents a real-time imaging system for THz radiation from BWO source. The key component of the system is the IR-FPA which is a bi-material MEMS detector array optimized for infrared wave lengths. In order to get a better THz image, the paper presents a modified FPA for THz region. Two main methods were explored to improve the detector performance in the THz region. The first way identified was the use of novel optical readout system based on SPR. The second detector improvement approach involved the change of the micro-cantilever structure that the cantilever of each pixel can shift in vertical direction. A model of one pixel was set up to optimize the structure. Computer simulations results show that both approaches are effective. The manufacturing of the proposed detector are also discussed. The technological investigation shows that it is feasible to employ sacrificial layer technique related to MEMS (Micro-Electro-Mechanical Systems) technology.