• An image sensor contributing to the development of ITER

The FURHI_VGA detector is a 10-bit digital colour image sensor in VGA format (contract in partnership with Fusion For Energy (F4E)). This detector is based on CMOS image sensors (CIS), for remote vision and inspection during the remote handling operations of the International Thermonuclear Experimental Reactor (ITER). F4E is responsible to the European Union (EU) for ITER, the world's largest scientific partnership to demonstrate that fusion is a viable and sustainable energy source.

ITER is a civil nuclear fusion research reactor project located in Cadarache (Bouches-du-Rhône). The research project is part of a long-term approach aimed at the industrialisation of nuclear fusion.

The FURHI_VGA detector is a radiation-resistant 10-bit digital VGA colour image sensor.

• An image sensor on the GEO-KOMPSAT-2B (Geostationary - Korea Multi-Purpose Satellite-2) satellite

The LARGO7M detector is a 7 million pixel image sensor that provides 2500km x 2500km images centred on South Korea with a resolution of 250m in different spectral bands (colours) from 370nm to 900nm. It enables short-term changes in the coastal environment around Korea to be observed, quantified, and predicted. The GEO-KOMPSAT-2B satellite was launched into orbit on 18 February 2020.

Mission lifetime: 10 years
Position: Geostationary orbit, 35,786 km above the Earth
Spectral bands: 12 bands in the visible spectrum
Ground resolution: 250m x 250m -over Korea
Target area: 2500km x 2500km

The image sensor is integrated by ADS with its proximity electronics and then placed in the telescope. A filter wheel selects the 12 spectral bands by placing a coloured filter in front of the 7 million pixel image sensor.

• An image detector in the COMS satellite (Communication, Ocean and Meteorological Satellite)

The COBRA2M detector is a 2 million pixel image sensor that provides 2500km x 2500km images centred on South Korea with a resolution of 500m in 8 different spectral bands (colours) from 400nm to 900nm. It is used to observe, quantify, and predict short-term changes in the coastal environment around Korea. The COMS satellite was launched into orbit on 27 June 2010.

Mission lifetime: 7 years
Position: Geostationary orbit, 35,786 km above the Earth
Spectral bands: 8 bands in the visible spectrum
Ground resolution: 500m x 500m above Korea
Target area: 2500km x 2500km

The image sensor is integrated by ADS with its proximity electronics and then placed in the telescope. A filter wheel selects the 8 spectral bands by placing a coloured filter in front of the 2 million pixel image sensor.

• An image detector in the SENTINEL 2A and 2B satellites

The VNIR S2 detector is a low-noise multi-array image sensor (contract in partnership with ADS and ESA). This sensor is on board two Sentinel 2 satellites, which observe the whole of the Earth's surface every 10 days, with a resolution of 10 m to 60 m, in 13 spectral bands ranging from the visible to the mid-infrared.

The data is mainly used in the fields of agriculture, forestry, land use, habitat characterisation, and biodiversity. They are also used to observe and prevent natural disasters, such as floods, volcanic eruptions, subsidence, and landslides. The Sentinel-2A and Sentinel-2B satellites were launched into orbit on 23 June 2015 and 7 March 2017 respectively.

Mission lifetime: 7.25 years for each satellite over a 20-year period
Principle of the instrument: Pushbroom
Position : Two identical satellites operating simultaneously, in phase at 180° to each other, in a sun-synchronous orbit at an average altitude of 786 km

Repetition cycle: 5 days at the equator, using the full configuration of the two-satellite constellation and in cloud-free conditions
Swath width: 290 km
Spectral bands: 13 spectral bands, ranging from visible and near-infrared to infrared
Ground resolution: 10, 20, 60 metres

There are 12 elementary sensors per focal plane in each satellite.

• An image detector in an aircraft to establish an optical link with the ARTEMIS geostationary satellite.

The LOLA (Liaison Optique Laser Aéroportée) project has established an optical link, via the atmosphere, between a Mystère XX aircraft and ESA's ARTEMIS geostationary satellite (prime contractor ADS). The APS 750 FAST CMOS sensor detects and tracks the satellite with a low level of received optical power. The wavelength of the communication beam is 850nm.

The physics of photodetection involves understanding and modelling, among other things:

• Charge generation in silicon
• The transfer of charges to the collection point (the photodiode), and the control of collection paths to avoid crosstalk
• The origin of the dark current in an attempt to reduce it
• How to design a photodiode, taking into account the materials used, in order to maximise its sensitivity, reduce the dark current, and maximise its total collection capacity

The means of understanding these phenomena, and even predicting them, are analytical modelling, physical mesh simulation (TCAD), and above all comparison with experimental data obtained using test structures or complete imagers.

• Optical nanostructures and CMOS image sensors: Improving photodetection or functionalities (spectral filters, polarization) using nanostructures integrated directly into each pixel. The structures are either integrated into the production flow or transferred to the top of the sensor.
• Methods used : Electromagnetic modelling using coupled waves and finite differences (Meep, Lumerical FDTD).
• Examples of integrated planar microlenses

Research linked to cryogenic activities covers several areas:

• Study of photodetection mechanisms for imagers used at extremely low temperatures (down to 80K) in the visible (VIS) and infrared (IR) wavelength ranges
• Study of innovative readout chains for extracting information from cooled imagers (ROIC)
• Extraction of physical models (physical simulation of semiconductors, TCAD) and electrical models (electrical simulation) of elementary microelectronic devices (MOSFET transistors, diodes, etc.)
• Development and optimisation of cryogenic temperature measurement methods (from 10K to 300K)