Planar double-slot antenna integrated into a Nb₅N₆ microbolometer THz detector

In this Letter, we propose and demonstrate a new type of planar double-slot antenna for a Nb₅N₆ microbolometer terahertz (THz) detector. The calculated results show that the planar antenna possessed high coupling efficiency, and the THz signals were obviously focused on the antenna center place. The new planar antenna was integrated with Nb₅N₆ microbolometer THz detectors using micro-fabrication technology. The measured results showed that the maximum optical voltage responsivity (R_o) of the detectors reached up to 113 V/W at 0.643 THz, and the corresponding noise equivalent power was 44pW/√Hz. In addition, the performance of double-slot antennas applied into array detectors in a tunable Fabry-Perot cavity was investigated. The measured results of the Nb₅N₆ THz detector remained almost unchanged when the distance between the chip substrate and the copper plate was altered. This indicated that this planar double-slot antenna, which possessed the advantages of high coupling efficiency and easy integration, has great application prospects in a THz detector.