Detectors of infrared radiation based on high T(c) superconducting YBCO films

We achieved control over the orientation and microstructure of the thin films of YBa2Cu30(7-x)(YBCO). We elucidated the optical properties of YBCO, including the penetration depth (which turned out to be rather small) and the optical anisotropy (which is rather large). We have observed photo-induced signals (i.e., changes in resistivity) of YBCO films in superconducting state as well as in the normal state upon illumination with short pulsed IR radiation generated by the Stanford free electron laser. Intensive work has been continued, and substantial advances made, in the construction of in-situ-growth facilities. Noise measurements have been made using films. The noise is found to increase markedly as the quality of the films deteriorates. Raman effect measurements and ellipsometric measurements, give further diagnostic information as to film quality and further understanding of the basic processes going on in the films.