Scaling Kinetic Inductance Detectors (KIDs)

For the last few decades, micro-channel plates (MCPs), charged coupled devices (CCDs), and hybrid complementary metal-oxide-semiconductor (CMOS) detectors have been the workhorses for collecting photons. More recently, the development of superconducting detectors such as the superconducting tunnel junctions (STJs) and transition edge sensors (TESs) has generated excitement in the imaging community. These detectors provide for simultaneous timing and spectral information as well as relatively good spectral energy resolution. However, STJs and TESs suffer from the major challenge of constructing large format arrays which are required for most imaging applications. Kinetic Inductance Detectors (KIDs) are a relatively new alternative superconducting technology that has many of the same desirable characteristics of STJs and TESs, and offer great promise for creating large-scale formats like current CCDs and CMOS detectors. The current approach for photon detection with KIDs uses a multiple frequency component activation signal. While this method has been proven to enable detection of photons, it has three key drawbacks that limit its utility in remote, size and power constrained applications. The first drawback is that each element of a KID array must be individually characterized under precisely controlled conditions. A second, even greater challenge is that the response of each KID element changes with temperature, necessitating in-system recalibration. Finally, current KIDs require 4-stage cryo-coolers in order to operate at mK temperatures, which are more challenging for space applications. New stimulation and detection approaches for arrays of high-temperature (~4K) KID sensors are being investigated to simplify the electronics required for the source signal and reduce the impact of even small changes in temperature. Simplification of sensor electronics will enable large and robust arrays of high-temperature KID sensors, opening new photon sensing opportunities in size, mass, and power-constrained applications. This paper describes the current state of SwRI's Internal Research and Development effort to develop a KID detector and associated support hardware.