| Popis: |
Corrugated quantum well IR photodetector (QWIP) focal plane arrays (FPAs) with cutoff wavelength of 11.2 and 16.2 micrometers were fabricated and tested. Each detector array has 256 X 256 pixel elements, indium bumped to a direct injection readout circuit manufactured by Rockwell Science Center. The rest of the supporting electronics were designed and built in-house to provide biases and clock functions to the FPAs. IR imageries with good aesthetic attributes were obtained from both FPAs. For the 11.2 micrometers FPA, background limited IR performance (BLIP) was obtained at 63 K under F/2 optics, consistent with the test results of a large area detector. This operating temperature is substantially higher than the grating coupled arrays with comparable cutoff wavelengths. On the other hand, the optics of the present camera were not optimized for wavelengths beyond 14 micrometers . As a result, the BLIP temperature for the 16.2 micrometers FPA, observed to be 38 K, was somewhat lower than the expected 42 K from the single detector characterization. Despite the reduced detector volume of a C-QWIP structure, the measured internal quantum efficiency remains to be high, being 20.5 percent and 25.4 percent at 2 V bias for the 11.2 micrometers and the 16.2 micrometers FPA, respectively. |
