Antenna-coupled uncooled Nb 5 N 6 microbolometers for terahertz imaging

In recent years our team has done a lot of work toward the goal of sensitive, inexpensive detectors for terahertz detection. In this paper we describe simple fabrication steps and the characterizations of uncooled Nb 5 N 6 microbolometers for terahertz imaging. The best dc responsivity of the Nb 5 N 6 microbolometer is –760 V/W at the bias current of 0.19 mA. A typical noise voltage as low as 10 nV/Hz 1/2 yields a low noise equivalent power (NEP) of 1.3×10 -11 W/Hz 1/2 at a modulation frequency above 4 kHz. We constructed a quasi-optical type receiver by attaching this uncooled Nb 5 N 6 microbolometer to the hyperhemispherical silicon lens. Subsequently, the imaging experiment is performed using this Nb 5 N 6 microbolometer receiver at a THz imaging system.