Operation of transition edge sensors in a resistance locked loop

TL;DR

This paper introduces a novel biasing method for superconducting transition edge sensors (TES) that maintains constant resistance via feedback, enhancing linearity and speed, especially in frequency domain multiplexed readout systems.

Contribution

It proposes a resistance locked loop biasing technique for TES, improving linearity and response speed over traditional voltage biasing methods.

Findings

Enhanced linearity in large signal response

Increased detector speed due to electrothermal feedback

Feasibility of cryogenic sinusoidal bias generation with SQUIDs

Abstract

We propose to operate a superconducting transition edge sensor (TES) using a different type of biasing, in which the resistance of the TES is kept constant by means of feedback on the bias voltage and is independent of the incoming signal power. By combining a large negative electrothermal feedback with a load independent resistance, this approach can significantly linearise the response of the detector in the large signal limit. The electrothermal feedback is enhanced in comparison with the commonly applied voltage biasing, which further increases the speed of the detector. Furthermore, in frequency domain multiplexed (FDM) readout, the sinusoidal bias voltages for each TES can be generated cryogenically with the readout SQUIDs.