Microwave detection using Y-Ba-Cu-O granular film bridge device

High-T-c superconducting microwave video detection is investigated based on the Y-Ba-Cu-O granular film bridge device. By optimizing the device parame ters, a detectivity of about 10(4) V/W is achievable, and the noise equival ent power at T = 70 K is about 5.2 x 10(-14) W/Hz(1/2). To identify the res ponse time of the device, the response voltage is measured with incident ra diation chopped at 500 kHz, and a rise time of less than 3.9 x 10(-8) s is observed. These results compare favorably with that of high-T-c superconduc ting bolometers for millimeter wave bands. On the other hand, the dynamic r esistance R-N of the device is found to increase as the device is illuminat ed by incident irradiation. This effect cannot be interpreted in terms of t he Josephson dissipation mechanism, and a discussion about this is presente d. (C) 2000 Elsevier Science B.V. All rights reserved.