FEASIBILITY OF A HIGH-TEMPERATURE BOLOMETER BASED ON BI2SR2CACU2O8+X SUPERCONDUCTING FILMS

The design of a high-temperature bolometer with large area that uses the resistive transition of a Bi2Sr2CaCu2O8+x superconducting thin film as a sensitive thermometer is discussed. Load curve analysis and discussion of nonthermal behavior are presented. Measurements of the electrical noise voltage spectrum and the analysis of the optical response performed with a chopped He-Ne laser at lambda = 633 nm gave a zero-frequency responsivity between 1.3 and 2.4 V/W and a noise equivalent power of 1 X 10(-8) W/Hz1/2 in the frequency range 2-10 Hz, with an effective time response of 1.5 s. Measurements of the excess noise voltage for different values of the bias current and temperature are used in order to predict the performances of a suitable bolometric composite architecture.