Investigation of reflection-based measurements of microwave kinetic inductance detectors in the optical bands

TL;DR

This study explores reflection-based measurement techniques for microwave kinetic inductance detectors (MKIDs), demonstrating reduced noise and improved energy resolution, which could enable more effective readout of large MKID arrays.

Contribution

It introduces reflection measurement configurations for MKIDs that reduce noise and enhance energy resolution compared to traditional transmission methods.

Findings

Reflection measurements reduce readout noise significantly.

Energy resolving power improves by 20-30% with reflection methods.

Reflection-based readout has potential for large MKID arrays.

Abstract

In this paper, we investigate the single photon response from the reflection of the Microwave Kinetic Inductance Detector (MKID) array. Reflection measurements are carried out using two configurations: one is measured simultaneously with the transmission, and the other is obtained with a single-ended MKID array terminated with an open load. Compared with the transmission, reflection measurements significantly reduce the readout noise of the single-ended MKID array. This is also reflected in the improvement of the median energy resolving power by around 20%-30% under pulsed photon illumination at $\lambda = 405$~nm, mainly due to an increase in the size of the resonance circle on the IQ plane. This method has the potential to be used to read out large MKID arrays.