A 25-micron single photon sensitive kinetic inductance detector

• DOI: 10.48550/arxiv.2404.10246
• Publication Date: 2024-01-01
• Authors: Day, Peter K.; Cothard, Nicholas F.; Albert, Christopher; Foote, Logan; Kane, Elijah; Eom, Byeong H.; Thakur, Ritoban Basu; Janssen, Reinier ...; Beyer, Andrew; Echternach, Pierre; van Berkel, Sven; Hailey-Dunsheath,...; Stevenson, Thomas R.; Dabironezare, Shahab; Baselmans, Jochem...; Glenn, Jason; Bradford, C. Matt; Leduc, Henry G.
• Keywords: Physics - Instrumentation and Detectors; FOS: Physical sciences; Instrumentation and Detectors (physics.ins-det); Astrophysics - Instrumentation and Methods for Astrophysics; Instrumentation and Methods for Astrophysics (astro-ph.IM)

35 pages, 18 figures<br/>We report measurements characterizing the performance of a kinetic inductance detector array designed for a wavelength of 25 microns and very low optical background level suitable for applications such as a far-infrared instrument on a cryogenically cooled space telescope. In a pulse counting mode of operation at low optical flux, the detectors can resolve individual 25-micron photons. In an integrating mode, the detectors remain photon noise limited over more than six orders of magnitude in absorbed power from 70 zW to 200 fW, with a limiting NEP of 4.6 x 10^-20 W/rtHz at 1 Hz. In addition, the detectors are highly stable with flat power spectra under optical load down to 1 mHz. Operational parameters of the detector are determined including the efficiency of conversion of the incident optical power into quasiparticles in the aluminum absorbing element and the quasiparticle self-recombination constant.<br/>