The thermal conversion efficiency in YBa2Cu3O7-delta microbridges for optical detection

For ideal mid-transition YBa2Cu3O7-delta (YBCO) optical detection, the maxi mum value of the photoresponse, Delta V-max, should linearly correspond to (d R/dT)(max) and the temperature rise Delta T be constant under the same m easurement conditions. However, in this study, both the experimental and si mulation results showed that the ratio of the temperature rise to irradiate d power density, Delta T/W-D, was no longer constant but was dependent on t he geometry of microbridges, which resulted in the nonlinearity of Delta V- max on (dR/dT)(max). Actually, Delta T/W-D represent the thermal conversion efficiency of the detector, and is a matter of the absorption of the RC th ermal irradiation and the dissipation of both the irradiation and the DC jo ule heat generated by the bias current. The competition between the capabil ity of heat dissipation and the thermal generation determined the magnitude of Delta T/W-D. The geometry plays a very important role on the behavior o f heat conduction, thermal conversion efficiency and photoresponse in YBCO microbridges.