Title :
Optical response of epitaxial and granular films of YBa2Cu3O7-δ at temperatures from 25 K to 100 K
Author :
Forrester, M.G. ; Gottlieb, M. ; Gavaler, J.R. ; Braginski, A.I.
Author_Institution :
Westinghouse Res. & Dev. Center, Pittsburgh, PA, USA
fDate :
3/1/1989 12:00:00 AM
Abstract :
The authors present the results of optical detection in epitaxial and granular films of YBa2Cu3O7-δ at wavelengths of 0.63, 3.39, and 10.6 μm and at temperatures from 25 K to 100 K. Both types of film exhibit only bolometric detection, with no evidence for nonequilibrium effects in this temperature range. For 0.63-μm radiation, mechanically chopped at 725 Hz, measurements of a 10×90 μm2 epitaxial bridge yield a bolometric responsivity of approximately 4×103 V/W, and detectivity D* of more than 108 cm√Hz/W. Granular films biased above their critical current are found to exhibit two-level switching noise, resulting in Lorentzian deviations from an otherwise 1/f noise spectrum
Keywords :
barium compounds; bolometers; high-temperature superconductors; infrared detectors; photodetectors; superconducting epitaxial layers; superconducting junction devices; superconducting thin films; yttrium compounds; 0.63 micron; 1/f noise spectrum; 10.6 micron; 25 to 100 K; 3.39 micron; Lorentzian deviations; YBa2Cu3O7-δ; bolometric detection; bolometric responsivity; critical current; detectivity; epitaxial bridge; epitaxial films; granular films; high temperature superconductor; optical detection; two-level switching noise; Bridges; Critical current; Current measurement; Mechanical variables measurement; Noise measurement; Optical detectors; Optical films; Radiation detectors; Temperature distribution; Wavelength measurement;
Journal_Title :
Magnetics, IEEE Transactions on
