Lumped Element Kinetic Inductance Detectors

Abstract

Kinetic Inductance Detectors (KIDs) provide a promising solution to the problem of producing large format arrays of ultra sensitive detectors for astronomy. Traditionally KIDs have been constructed from superconducting quarter-wavelength or half-wavelength resonator elements capacitivly coupled to a co-planar feed line. Photons are detected by measuring the change in quasi-particle density caused by the splitting of Cooper pairs in the superconducting resonant element. This change in quasi-particle density alters the kinetic inductance, and hence the resonant frequency of the resonant element. This arrangement requires the quasi-particles generated by photon absorption to be concentrated at positions of high current density in the resonator. This is usually achieved through antenna coupling or quasi-particle trapping. For these detectors to work at wavelengths shorter than around 500 μm where antenna coupling can introduce a significant loss of efficiency, then a direct absorption method needs to be considered. One solution to this problem is the Lumped Element KID (LEKID), which shows no current variation along its length and can be arranged into a photon absorbing area coupled to free space and therefore requiring no antennas or quasi-particle trapping. This paper outlines the relevant microwave theory of a LEKID, along with theoretical performance for these devices.

Bi-layer kinetic inductance detectors for space observations between 80–120 GHz

“…For a detailed study of the parameters that determine the responsivity of a LEKID we refer to Doyle et al (2007Doyle et al ( , 2008.…”

Quasi-optical analysis of a far-infrared spatio-spectral space interferometer concept

“…A number of detector technologies would suit the FISICA sensitivity and bandwidth needs, with the leading technologies being TES's (transition edge sensors) and KID's (kinetic inductance devices). TES's currently have a higher TRL (technology readiness level) [23], but there is a lot of promise for the future of KID's [24] for a FISICA-type system. For the purposes of the current work, smooth walled, conical horns of length L = 4.0 mm and aperture a = 0.375 mm (see Figure 4 (right)) were positioned on the focal plane in the PO model.…”

Ultra Low Background Cryogenic Test Facility for Far-Infrared Radiation Detectors

“…A MKID consists of a thin superconducting film that is incorporated in a resonance circuit with a typical resonance frequency of a few GHz [2,5]. Changes in the surface impedance of the film due to Cooper pair breaking caused by radiation absorption are converted to changes in resonator quality factor and resonance frequency read out at the resonator resonance frequency.…”