Cryogenic LED pixel-to-frequency mapper for kinetic inductance detector arrays
Jiansong Gao, Xiangliang Liu, W Guo, Wei L.F., Christopher M. McKenney, Bradley J. Dober, Tasha Billings, Johannes Hubmayr
We present a cryogenic wafer mapper based on light emitting diodes (LEDs) for mapping a large microwave kinetic inductance detector (MKID) array. In this scheme, an array of LEDs, addressed by DC wires and collimated through horns onto the detectors, are mounted in front of the detector wafer. By illuminating the LED individually and sweeping the frequency response of all the resonators, we can unambiguously correspond a detector pixel to its measured resonance frequency. We have demonstrated mapping a 75~mm $90$-pixel MKID array using a mapper containing $126$ LEDs with $16$ DC bias wires. Our LED wafer mapper has no moving parts and is easy to implement. It may find broad applications in superconducting detector and quantum computing/information experiments.