Review of the state of infrared detectors for astronomy in retrospect of the June 2002 workshop on scientific detectors for astronomy

Only two months ago, in June 2002, a workshop on scientific detectors for astronomy was held in Waimea, where for the first time both experts on optical CCD's and infrared detectors working at the cutting edge of focal plane technology gathered. An overview of new developments in optical detectors such as CCD's and CMOS devices will be given elsewhere in these proceedings. This paper will focus on infrared detector developments carried out at the European Southern Observatory ESO and will also include selected highlights of infrared focal plane technology as presented at the Waimea workshop. Three main detector developments for ground based astronomers are currently pushing infrared focal plane technology. In the near infrared from 1 to 5 μm two technologies, both aiming for buttable 2K x 2K mosaics, will be reviewed, namely InSb and HgCdTe grown by LPE or MBE on Al 2 O 3 , Si or CdZnTe substrates. Blocked impurity band Si:As arrays cover the mid infrared spectral range from 8 to 28 μm. Since the video signal of infrared arrays, contrary to CCD's, is DC coupled, long exposures with IR arrays are extremely susceptible to drifts and low frequency noise pick-up down to the mHz regime. New techniques to reduce thermal drifts and suppress low frequency nosie with on-chip reference pixels will be discussed. The need for the development of small format low noise sensors for adaptive optics and interferometry will be pointed out.