HIGH T-C YBA2CU3O7-DELTA SUPERCONDUCTING TRANSITION-EDGE MICROBOLOMETERS

High T-c superconducting thin film YBa2Cu3O7-delta (YBCO) bolometers h ave been fabricated on various substrates such as MgO, LaAlO3, YSZ and Si using laser ablation technique. Performance of these IR bolometers operating with a Joule-Thomson refrigerator has been investigated. Me asurements of the responsivity and low frequency noise near T-c in the current biased YBCO bolometers show that reliable devices can be fabr icated. Measured noise equivalent power (NEP), for YBCO/YSZ bolometer, reaches 6 x 10(-10) W/Hz(1/2) at 165 Hz and has a responsivity of 60 V/W with a blackbody source. This performance is comparable to that of the optimized pyroelectric detectors. The characteristics of YBCO fil ms deposited on Si substrates reveal that superconducting thin film mu lti-elements or focal plane array with silicon integrated readout circ uit are feasible. Such bolometers exhibit NEP of 7 x 10(-9) W/Hz(1/2), and significant improvement appears possible. Electrical measurements show no noticeable film degradation after the bolometer is exposed to atmosphere for three months.