Benefits of bolometer Joule stepping and Joule pulsing

Abstract

We introduce the `Joule stepping' technique, whereupon a constantly-biased bolometer has its bias voltage modified by a small additional step. We demonstrate this technique using a composite NTD semiconductor bolometer and a pulsing device which sends an extra step in voltage. We demonstrate the results of the technique over a range of bias voltages at 100, 200, and 300 mK. We find that Joule stepping allows us to directly measure long thermal tails with low amplitudes in the bolometer response, and could be a useful tool for quickly and easily understanding response functions of bolometric detectors. We also show that the derivative of the Joule step is equivalent to the bolometer response to a $\delta$-pulse (or Joule pulse), which allows for greater understanding of fast transient behaviour.