Detectors for the astronomical applications

Astronomical observations are dependent on focal-plane instruments, and detectors continue to play a key role. The detector technology is evolving rather fast with the large-format CMOS and CCD array mosaics, electron-multiplying CCDs, electron-avalanche photodiode arrays, quantum-well IR photon detectors etc. However, the requirements of artifact-free photon shot noise limited images are the higher sensitivity, higher quantum efficiency, reduced noise that includes dark current, read-out and amplifier noise, smaller point-spread functions and higher spectral bandwidth, etc. One of the fastest growing applications is signal sensing, particularly wavefront sensing for adaptive optics and fringe tracking for interferometry. A few detectors that are being used in astronomical imaging are discussed in this talk.