Antenna-coupled high-T c air-bridge microbolometer on silicon

An antenna-coupled high-Tc superconducting microbolometer on a silicon substrate, operating at infrared wavelengths, is described. This detector incorporates a silicon-micromachined yttria-stabilized zirconia air bridge at the feed of a planar lithographic antenna to simultaneously minimize the thermal conductance and the heat capacity of the bolometer. At an operating temperature of 87.4 K, the optical responsivity measured using a 300-K blackbody source over a 0.2–2.9 THz bandwidth is 2900 V/W, the optical noise-equivalent power (NEP) is 9×10−12 W/Hz1/2, and the time constant is <10 μs. This NEP is nearly a factor of 2 lower than the previous record for a liquid-nitrogen-cooled thermal detector, and the time constant is several orders of magnitude shorter.