High-sensitivity transition-edge-sensed bolometers: improved speed and characterization with AC and DC bias

TL;DR

This paper presents improvements in the speed of transition-edge-sensed bolometers through a new fabrication process and detailed characterization using AC and DC bias methods, achieving faster response times but with increased noise.

Contribution

The study introduces a fabrication process that reduces heat capacity without dry etching and employs a novel near-IR photon-noise calibration technique for AC and DC systems.

Findings

Reduced detector time constant to 3.2 ms

Achieved NEP of 0.8 aW/rtHz with low 1/f noise

Increased thermal conductance and NEP due to new fabrication

Abstract

We report on efforts to improve the speed of low-G far-infrared transition-edged-sensed bolometers. We use a fabrication process that does not require any dry etch steps to reduce heat capacity on the suspended device and measure a reduction in the detector time constant. However, we also measure an increase in the temperature-normalized thermal conductance (G), and a corresponding increase in the noise-equivalent power (NEP). We employ a new near-IR photon-noise technique using a near-IR laser to calibrate the frequency-domain multiplexed AC system and compare the results to a well-understood DC circuit. We measure an NEP white noise level of 0.8 aW/rtHz with a 1/f knee below 0.1 Hz and a time constant of 3.2 ms.