Detectivity of YBCO Transition Edge Bolometer as a Function of Chopping Frequency, Bias Current and Coating

Bolometric response and noise characteristics of YBCO superconductor transition edge IR detectors with relatively sharp transition and its resulting detectivity are investigated. The magnitude of response of a device was obtained in different bias currents and modulation frequencies. Also dependency of intrinsic noise of the device with respect to the bias temperature in the vicinity of critical temperature was studied for various values of bias currents and chopping frequencies. Having measured the bolometric response and noise characteristics, we found the device detectivity versus frequency in different bias currents and analyzed the results. We also improved the detectivity of the device by increasing surface absorptance using a novel infrared absorber, which is made of a Copper-Carbon composite, coated in a low temperature process. Within the modulation frequency range studied in this investigation, comparison of device responsivity before and after the coating is also presented.

Keywords:

Bolometer , IR detectivity , Infrared absorber , Noise