Influence of substrate thickness on the responsivity of antenna-coupled THz microbolometers

We report on the influence of substrate thickness on the performance of antenna coupled microbolometers for terahertz (THz) detection. Planar antennas with NbsNó microbolometers were fabricated on silicon substrates. Detected voltages of these antenna-coupled microbolometers are altered with a periodic variation from 0.5 THz to 0.75 THz, which is accorded with the reflection of the substrate. By placing a piece of movable metallic slab behind the device, which results in a tunable thickness of the substrate, we can improve the voltage responsivity of the device at a given frequency.