Terahertz Direct Detection in ${\hbox{YBa}}_{2}{\hbox{Cu}}_{3}{\hbox{O}}_{7}$ Microbolometers

Abstract

A high sensitivity broadband terahertz direct detector based on YBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> high-Tc superconductor microbolometers is presented. At 77 K, the responsivity of the spiral antenna-integrated microbolometers (1.5 μm ×1.5 μm) is 190 V/W, referenced to the input of the silicon substrate lens, across the frequency range of 330 GHz-1.63 THz in a single device. The response time is approximately 300 ps. Using a room temperature readout, we measure an optical noise equivalent power (NEP) of 20 pW/Hz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sup> (readout noise limited) for modulation frequencies ranging from 500 Hz to 100 kHz.