15-um cut-off 128 x 128 quantum well infrared photodetectors (QWIPs) camera

We discuss the development and the performances of a very long wavelength (13.5 - 15 micrometer) 128 by 128 AlGaAs/GaAs multiquantum well infrared imaging system. A highly uniform, high-yield QWIP focal plane array was hybridized to a CMOS multiplexer operating in a direct injection mode. For efficient light coupling an integral random scattering reflector (random grating) was incorporated. Due to the high uniformity, excellent imagery, low noise as well as a noise equivalent temperature difference (NE(Delta) T) of less than 30 mK were obtained when operating around 45 K. Therefore, high image contrast signal to noise ratio has been achieved.