Infrared focal plane technology has evolved rapidly in the past two decades. The detector format has grown from single pixel detectors to 4K × 4K pixel arrays, and a mosaic of 4 × 4 2K × 2K pixel arrays and six mosaics of 2 × 2 2K × 2K pixel arrays are already in operation at ground based telescopes. The quantum efficiency of these arrays is close to 100%, the readout noise a few electrons rms and the dark current a few electrons per hour. However, the latent image problem has not been solved yet. A persistence model and a mitigation strategy will be discussed briefly. Specialized ASIC readout chips which digitize the multichannel video signals of large arrays directly on the focal plane are becoming available for large format arrays and they will eventually replace conventional controllers. In the mid infrared a high flux version of the MIRI detector is being developed for ground based applications. Fast low noise infrared sensors are needed for wavefront sensors of adaptive optics (AO) systems. To meet both the speed and the noise requirements two different technical approaches are being followed. One solution is the use of high gain CTIA amplifiers in the detector unit cell, the other solution is to exploit the noiseless gain mechanism of HgCdTe electron avalanche photodiode (eAPD) arrays.

This document is a recap of an oral presentation made at Nice duringthe INSU Astrophysics Detector Workshop 2008. It aims at giving anoverview of the achievements and ongoing developments presently carriedout at CEA-LETI in the field of Infrared focal plane array. Althoughmost of the research actually performed at LETI is not driven by spaceoriented application, the excellence and the cutting edge of the outcomeis or can be applied to space-dedicated components. This paper focuson features and developments from which astrophysics observation wouldbenefit in the near future on the European market. This encompassed“traditionnal” developments such as format enlargement, low dark currenttechnology such as p/n structure but it also shade light on promisingand thrilling development such as avalanche photodiode array. It eventuallygives some hints of none MCT technologies processed at LETI.

For a variety of scientific, space and defence applications, there is an increasing demand for long-wavelength infrared (LWIR) detector focal plane arrays and compact infrared instruments. In the first part, we present an overview of alternative detectors to standard mercury cadmium telluride photodiodes for LWIR detection, such as the HgCdTe avalanche photodiode, the quantum-well infrared photo-detectors, the superlattice detectors and the carbone nanotubes-based bolometers. In the second part, we focus on new concepts developed to meet the requirement of miniaturization of infrared instruments. Original IRFPA-based micro-optical assemblies have been achieved, demonstrating several optical functions such as imagery, spectral filtering, spectrometry and wavefront sensing.

In the JDEM context, a Integral Field Spectrograph has been proposed to study Supernovae. The performances of this instrument are strongly connected with its detector characteristics. The large R&D effort in the SNAP collaboration combined with the performances improvement of Teledyne H2RG infrared detectors indicates that those devices are now able to reach the requirements of the JDEM/SNAP spectrograph.

This paper is a presentation of the activity that has been performed in the domain of Blocked Impurity Band detector, from the operating principle to the characterization. This study has been performed commonly with IMEC in Belgium, MPIA Heidelberg and Thales Alenia Space in Cannes. The presentation deals with:

• A brief description of the context and the organization of thestudy.

• A description of the BIB detector operating principle.

• A short presentation of the technological steps for the detector fabrication.

• The main outcomes of the experimentation at diode level and at array level.

VIHI: the Visible and Infrared Hyperspectral Imager is one of the three channels of the Simbio-Sys instrument for the BepiColombo mission to Mercury. Its scientific objective is to study the hermean surfaces composition by sensing the photon flux reflected off the planet. VIHI works in the range of 400 to 2000 nm with a spectral resolution around a few hundreds. The particularity of this channel is the use of a single detector matrix (264 × 264) for both visible and infrared wavelengths. Getting the visible part of the detector responsivity is achieved by thinning an infrared HgCdTe matrix because visible light is completely absorbed inside the substrate. The thinning process is well controlled since a long time and was used to increase number of thermal cycle of the hybrid devices. Recently, this process is able to remove completely the substrate and, thus, open the detector to the visible range. The detector is a custom design made by Raytheon Vision System in Goleta (USA). In this paper, we will describe the expected performances of the detector which is designed to work in the very harsh radiation environment of Mercury.