Responsivity and Noise Equivalent Power of a Single Cold-Electron Bolometer

Abstract

We have developed a single-pixel capacitively coupled Cold-Electron Bolometer (CEB) and characterized it in the current-biased regime. The most attractive feature of the CEB is effective electron self-cooling of the absorber, which leads to a lower bolometer noise and higher dynamic range. The bolometer responsivity was measured by determining the voltage response to an applied power through the absorber from a heating current, modulated at frequencies from 35 Hz to 2 kHz. The optimum responsivity of 1.5 × 1010 V/W was measured at a modulation frequency of 35 Hz. The noise equivalent power (NEP) was subsequently obtained from the estimated bolometer noise voltage with respect to the measured bolometer responsivity. The NEP of better 2 × 10−18 W/Hz1/2 was obtained for modulation frequencies greater than 100 Hz. The background power and the bolometer time constant were also estimated from the experimental results. The photon-noise-limited operation of CEB will dominate for a signal power of 10 fW and higher at frequency 80 GHz and higher.