publications

Multisource neural network feature map fusion: An efficient strategy to detect plant diseases

August 2023 - Guillaume Heller et al., CRESTIC EA 3804, Université de Reims Champagne Ardenne, France

Abstract: The use of RGB cameras or multispectral imaging systems can provide a wide range of applications for crop monitoring, plant phenotyping and disease detection. Although several approaches have been proposed, they increasingly use convolutional neural network-based architectures, which have, however, become increasingly cumbersome for improving classification results and difficult to train with few labeled data. Other increasingly popular approaches consist of using an ensemble of convolutional neural networks, in which each model solves a different problem. Since the inference is time- and resource-consuming due to the execution of multiple models, recent works have focused on transferring knowledge from an ensemble of models to a compact model to obtain better performance. In this paper, we propose an original approach that improves both accuracy and speed by reusing feature maps extracted by heterogeneous models from different data.

RedEye-1: a compact SWIR hyperspectral imager for observation of atmospheric methane and carbon dioxide

2 Nov. 2023 - Naif Alsalem et al., ARC Training Centre for CubeSats, UAVs and Their Applications (CUAVA), School of Physics, University of Sydney, Australia

Abstract: We present the development of our first prototype of a compact short-wavelength infrared (SWIR) hyperspectral imager, RedEye-1, designed to observe and measure the concentrations of methane (CH4) and carbon dioxide (CO2) in the atmosphere. It operates in the spectral range of 1588 nm to 1673 nm with a nominal spectral resolution of 0.5 nm and has a total weight of approximately 1.8 kg.

Nonlinear Wave Front Reconstruction from a Pyramid Sensor using Neural Networks

November 2023 - by Alison P.Wong et al., Sydney Institute for Astronomy, School of Physics, University of Sydney, Australia

Abstract: The pyramid wave front sensor (PyWFS) has become increasingly popular to use in adaptive optics (AO) systems due to its high sensitivity. The main drawback of the PyWFS is that it is inherently nonlinear, which means that classic linear wave front reconstruction techniques face a significant reduction in performance at high wave front errors, particularly when the pyramid is unmodulated. In this paper, we consider the potential use of neural networks (NNs) to replace the widely used matrix vector multiplication (MVM) control.

Characterization of a C-RED One camera for astrophotonical applications

2023 (Astronomische Nachrichten - DOI: 10.1002/asna.20230124) - by S.Vješnica, innoFSPEC–Technical Section/Detector Systems, Leibniz-Institut für Astrophysik Potsdam (AIP), Germany

Abstract: To better understand the impact of the avalanche gain applied in the detector technology and apply this technology in our in-house astrophotonic projects, we have characterized a C-RED One camera and produced a stable and reliable method for calculating the system gain at any desired avalanche gain setting.

Remote Nanoscopy with Infrared Elastic Hyperspectral Lidar

2023 (Advanced Science - DOI: 10.1002/advs.202207110) - by Lauro Müller et al., Department of Physics, Lund University, Sweden

Abstract: Monitoring insects of different species to understand the factors affecting their diversity and decline is a major challenge. Laser remote sensing and spectroscopy offer promising novel solutions to this. Coherent scattering from thin wing membranes also known as wing interference patterns (WIPs) have recently been demonstrated to be species specific. The colors of WIPs arise due to unique fringy spectra, which can be retrieved over long distances. To demonstrate this, a new concept of infrared (950–1650 nm) hyperspectral lidar with 64 spectral bands based on a supercontinuum light source using ray-tracing and 3D printing is developed.

C-RED 3: Demonstrating the first 24-hour continuous vertical monitoring of the atmospheric optical turbulence

February 2023 - by R.Griffiths et al., Department of Physics, Centre for Advanced Instrumentation, Durham University.

Abstract: We report what is believed to be the first example of fully continuous, 24-hour vertical monitoring of atmospheric optical turbulence. This is achieved using a novel instrument, the 24-hour Shack-Hartmann Image Motion Monitor (24hSHIMM). Optical turbulence is a fundamental limitation for applications such as free-space optical communications, where it limits the achievable bandwidth, and ground-based optical astronomy, restricting the observational precision. Knowledge of the turbulence enables us to select the best sites, design optical instrumentation and optimise the operation of ground-based optical systems.

Sub-electron noise infrared camera development using Leonardo large format 2Kx2K SWIR LmAPD array

July 2022 (Proceedings SPIE ATI) - by P. Feautrier, JL. Gach, et al.

There have been no significant breakthroughs in infrared imagery since the hybridization of III-V or II-VI narrow bandgap semiconductors on complementary metal-oxide semiconductor (CMOS) read-out integrated circuits (ROICs). The development of third-generation, linear-mode avalanche photodiode arrays (LmAPDs) using mercury cadmium telluride (MCT) has resulted in a significant sensitivity improvement for short-wave infrared (SWIR) imaging. The first dedicated LmAPD device, called SAPHIRA (320x256/24μm), was designed by Leonardo UK Ltd specifically for SWIR astronomical applications requiring speed and sensitivity. In the past decade there has been a significant development effort to make larger LmAPD arrays for low-background astronomy and advance adaptive optics.

C-RED One: Last performances improvement of the camera using the 320x256 e-APD infrared Saphira detector

July 2022 (Proceedings SPIE ATI) - by P. Feautrier & JL. Gach

We present here the latest results obtained with the C-RED One camera developed by First Light Imaging for fast ultralow noise infrared applications. This camera uses the Leonardo Saphira e-APD 320x256 infrared sensor in an autonomous cryogenic environment with a low vibration pulse tube and with embedded readout electronics system. Some recent improvements were made to the camera.

C-RED 2 ER: high speed extended range InGaAs cameras

July 2022 (Proceedings SPIE ATI) - by I. De Kernier et al.

MCT-based cameras are very competitive when it comes to ultra-low light imaging, however it is crucial for less demanding applications to have a non-cryogenic and cost-effective solution. Progress in band-gap engineering has enabled to shift the detection cut-off wavelength of InGaAs by tuning the indium composition of the InxGa1-xAs compound. Operating with a double TEC coupled to air and water cooling, the C-RED 2 Extended Range cameras are an alternative to MCT for specific applications in astronomy and free space optics. We will present the performances of these new VGA extended range InGaAs cameras with sensitivity from 1.1 μm to 1.9 μm and from 1.2 μm to 2.2 μm.

C-BLUE 3 PC : a photon counting multimegapixel visible CMOS camera

July 2022 (Proceedings SPIE ATI) - by JL Gach, I. De Kernier and P.Feautrier

The photon counting imaging paradigm in the visible and the infrared comes from the very small energy carried by a single photon at these wavelengths. Usually to detect photons the photoelectric effect is used. It converts a photon to a single electron making it very difficult to detect because of the readout noise of the electronics. To overcome this there are two strategies, either to amplify the signal to make it larger than the readout noise (used in the so called gain or amplified detectors), or to lower the readout noise in a standard image sensor.

C-BLUE One : A family of CMOS high speed cameras for wavefront sensing

July 2022 (Proceedings SPIE ATI) - by JL Gach et al

We present the evolutions of the C-BLUE One family of cameras (formerly introduced as C-MORE), a laser guide star oriented wavefront sensor camera family. Within the Opticon WP2 european funded project, which has been set to develop LGS cameras, fast path solutions based on existing sensors had to be explored to provide working-proven cameras to ELT projects ready for the first light schedule. Result of this study, C-BLUE One is a CMOS based camera with 1600x1100 pixels (9um pitch) and 481 FPS refresh rate.

MYSTIC: a high angular resolution K-band imager at CHARA

August 2022  (Proceedings SPIE ATI) - by B.R. Setterholm et al., University of Michigan, Department of Astronomy, Ann Arbor, USA

The Michigan Young STar Imager at CHARA (MYSTIC) is a K-band interferometric beam combining instrument funded by the United States National Science Foundation, designed primarily for imaging sub-au scale disk structures around nearby young stars and to probe the planet formation process.

AO3000 at Subaru: Combining for the first time a NIR WFS using First Light’s C-RED ONE and ALPAO’s 64x64 DM

September 2022 (Preprint  arXiv:2209.12981v1) - by J.Lozi et al.

After 16 years of on-sky operation, Subaru Telescope’s facility adaptive optics AO188 is getting several major upgrades to become the extreme-AO AO3000 (3000 actuators in the pupil compared to 188 previously). AO3000 will provide high-Strehl images for several instruments from visible to mid-infrared, notably the Infrared Camera and Spectrograph (IRCS), and the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO). For this upgrade, the original 188-element deformable mirror (DM) will be replaced with ALPAO’s 64 × 64 DM. The visible wavefront sensor will also be upgraded at a later date, but in the meantime we are adding a near-infrared Wavefront Sensor (NIR WFS), using either a double roof prism pyramid mode or a focal plane WFS mode. This new wavefront sensor will use for the first time First Light’s C-RED ONE camera, allowing for a full control of the 64 × 64 DM at up to 1.6 kHz.

Performance of a complementary metal-oxide-semiconductor sensor 2 for laser guide star wavefront sensing

May 2022 (Preprint of HAL Open Science - hal-03669641) - by Ke et al.

Abstract: The adaptive optics (AO) systems of future Extremely Large Telescopes (ELTs) will be assisted with laser guide stars (LGS) which will be created in the sodium layer at a height of ~90 km above the telescopes. In a Shack-Hartmann wavefront sensor, the long elongation of LGS spots on the sub-pupils far apart from the laser beam axis constraints the design of the wavefront sensor (WFS) which must be able to fully sample the elongated spots without undersampling the non-elongated spots. To fulfill these requirements, a newly released large complementary metal oxide semiconductor (CMOS) sensor with 1100x1600 pixels and 9 µm pixel pitch could be employed.

C-RED 2 ER : an extended range SWIR camera with applications in hyperspectral imaging

March 2022 (Proc. of SPIE Vol. 11997, 119970V Photonics West 2022) by Isaure de Kernier, Yann Wanwanscappel, David Boutolleau, Thomas Carmignani, Fabien Clop, Philippe Feautrier, J.L. Gach, Stephane Lemarchand, Eric Stadler (First Light Imaging)

Abstract: The development of extended range detectors based on InGaAs technology is a recent breakthrough in imaging. Taking advantage of the technological bricks developed for the C-RED 2 camera, First Light Imaging has integrated extended range InGaAs sensors and explored the possibilities offered by this technology. The C-RED 2 ER camera can support two detectors with shifted sensitivity. The cameras and their performances are described in detail in this paper.

Current status of PAPYRUS : the pyramid based adaptive optics system at LAM/OHP

October 2021 - arXiv:2110.10263v1 [astro-ph.IM] - by E. Muslimov et al.

Abstract: The Provence Adaptive optics Pyramid Run System (PAPYRUS) is a pyramid-based Adaptive Optics (AO) system that will be installed at the Coude focus of the 1.52m telescope (T152) at the Observatoire de Haute Provence (OHP). The project is being developed by PhD students and Postdocs across France with support from staff members consolidating the existing expertise and hardware into an R&D testbed. This testbed allows us to run various pyramid wavefront sensing (WFS) control algorithms on-sky and experiment on new concepts for wavefront control with additional benefit from the high number of available nights at this telescope.

CUAVA InGaAs-based, Short Wavelength Infrared (SWIR) Instrument for Atmospheric Reconnaissance

June 2021 (Proceedings of SPIE - International Conference on Space Optics 2021) - by N.Alsalem et al., ARC Training Centre for CubeSats, UAVs & Their Applications (CUAVA), University of Sydney, Australia

Abstract: We report the preliminary design of a new small-size remote sensing instrument operating in the Short Wavelength Infrared (SWIR) domain of the spectrum (1.588 μm to 1.673 μm) to monitor, detect, and measure atmospheric constituents such as Carbon Dioxide (CO2) and Methane (CH4) concentrations. We highlight the instrument features, technical specifications (including a relatively high spectral resolution of approximately 0.4 nm), optical design, and components.

CHARA/MIRC-X: a high-sensitive six telescope interferometric imager concept, commissioning and early science

July 2020 (Proc. of SPIE Vol. 11446 SPIE Astronomical Telescopes + Instrumentation Online)- by N. Anugu et al

Abstract: MIRC-X is a six telescope beam combiner at the CHARA array that works in J and H wavelength bands and provides an angular resolution equivalent to a B=331m diameter telescope. The legacy MIRC combiner has delivered outstanding results in the fields of stellar astrophysics and binaries. However, we required higher sensitivity to make ambitious scientific measurements of faint targets such as young stellar objects, binary systems with exoplanets, and active galactic nuclei.

A pathfinder for imaging exo-Earths - SCExAO / SUBARU Telescope

May 2019 - An article by Thayne Currie, NASA Ames Research Center, Mountain View, CA, USA - Published in Nature Astronomy (VOL 3)

Abstract: Over the past ten years, high-contrast imaging systems and now dedicated extreme adaptive optics (AO) systems on ground-based telescopes have revealed the first direct detections of young, self-luminous Jovian extrasolar planets on Solar System-like scales, up to one million times fainter than the stars they orbit...

On-sky verification of Fast and Furious focal-plane WFS: Moving forward toward controlling the island effect at Subaru/SCExAO

March 2020 - S. P. Bos et al.: On-sky verification of “Fast & Furious” focal-plane wavefront sensing - Published on Astronomy & Astrophysics / EDP Sciences

Abstract: High-contrast imaging (HCI) observations of exoplanets can be limited by the island effect (IE). The IE occurs when the main wavefront sensor (WFS) cannot measure sharp phase discontinuities across the telescope’s secondary mirror support structures (also known as spiders). On the current generation of telescopes, the IE becomes a severe problem when the ground wind speed is below a few meters per second...

MIRC-X: a highly-sensitive six telescope interferometric imager at CHARA

July 2020 - A scientific paper by N. Anugu et al.

Abstract: MIRC-X (Michigan InfraRed Combiner-eXeter) is a new highly-sensitive six-telescope interferometric imager installed at the CHARA Array that provides an angular resolution equivalent of up to a 330m diameter baseline telescope in J and H band wavelengths. We upgraded the original MIRC (Michigan InfraRed Combiner) instrument to improve sensitivity and wavelength coverage in two phases. First, a revolutionary sub-electron noise and fast-frame rate C-RED ONE camera based on a SAPHIRA detector was installed...

C-RED 3: A SWIR camera for FSO applications

February 2020 (11272-14 SPIE Photonics West 2020) by J.L. Gach, David Boutolleau, Cecile Brun, Thomas Carmignani, Fabien Clop, Philippe Feautrier, Stephane Lemarchand, Eric Stadler, Yann Wanwanscappel (First Light Imaging, LAM, IPAG)

Abstract: Free space communications (FSO) is interesting for distant applications where high bandwidth is needed while using a fiber is not possible. However these links have to face several issues, and the most important one is the beam scintillation due to the propagation through a turbulent media, the atmosphere. Several mitigation strategies have been developed, but the best way to suppress scintillation is to use adaptive optics, widely used now in astronomy. The main difficulty for FSO is to probe the wavefront fast enough to have a good turbulence correction. This was not possible due to the lack of wavefront sensors working in the SWIR. C-RED 3 is a 640x512 SWIR camera running at 600FPS full frame and has the legacy of all the developments of astronomical infrared fast wavefront sensors on top of specific features for FSO (Low SWaP, Low Cost).

Characterization of the C-RED 2: a high-frame rate near-infrared camera

November 2019 - A Scientific paper from Rose K. Gibson, Rebecca Oppenheimer, Christopher T. Matthews, Gautam Vasisht (Columbia University, American Museum of Natural History, Jet Propulsion Laboratory, California Institute of Technology- United States) Published in the Journal of Astronomical Telescopes, Instruments and Systems 011002-1

Abstract. A wave of precision radial velocity (RV) instruments will open the door to exploring the populations of companions of low-mass stars. The Palomar Radial Velocity Instrument (PARVI) will be optimized to detect RV signals of cool K and M stars with an instrument precision floor of 30 cm∕s. PARVI will operate in the λ ¼ 1.2- to 1.8-μm-wavelength range with a spectral resolution of λ∕Δλ ∼ 100;000. It will operate on the Palomar 5.1-m Hale telescope and use Palomar’s PALM-3000 adaptive optics system, single-mode fibers, and an H-band laser frequency comb to probe and characterize the population of planets around cool, red stars. We describe the performance of the PARVI guide camera: a C-RED 2 from First Light Advanced Imagery.

Performance analysis of 349-element adaptive optics unit for a coherent free space optical communication system

September 2019 - An article from Lequiang Yang et al., Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences - Published on Nature Research (Scientific Reports - Article 13150 (2019) www.nature.com/articles/s41598-019-48338-3)

Abstract: As a continuation of our previous work [Optics Express.25, 15229(2017)] in which we have verified the performance of a coherent free space optical communication (FSOC) system with a 97-element adaptive optics (AO) system, in this paper, we evaluated the performance improvement of the coherent FSOC system using a large-scale high-speed AO system with a 349-element continuous surface deformable mirror. The mixing efficiency (ME) and bit-error-rate (BER) under different Greenwood frequency (GF) were calculated as the performance metric of coherent FSOC system. The performance of FSOC system using such a large-scale AO system was quantitatively verified for the first time. The obtained results showed that the performance was obviously improved when a larger-scale high-speed AO system is employed in coherent FSOC system. This analysis result provides a performance verification for large-scale high-speed AO systems used in FSOC system which is beneficial for coherent FSOC system parameters design.

Imaging single carbon nanotubes with C-RED 2

September 2019 - Antony Lee and Laurent Cognet from LP2N Laboratoire Photonique Numérique et Nanosciences (University of Bordeaux, Institut d'Optique & CNRS) report on their work with C-RED 2 for single carbon nanotubes infrared (SWIR) imaging with an InGaAs camera

Abstract: In recent years, single-walled carbon nanotubes (SWCNT) have been established as remarkable fluorophores for probing the nanoscale organization of biological tissues1,2.They are stiff, quasi-one-dimensional nanostructures, with a small diameter (~1nm) which enables excellent penetration into complex environments, and a large length (100nm to 1μm) which slows down their diffusion and thus allows the tracking of single fluorescent particles. Finally, their bright and stable near-infrared (NIR) fluorescence allows long-term tracking deep in biological tissues without suffering from biological autofluorescence.

C-MORE : the laser guide star wavefront sensor

June 2019 (AO4ELT 6 - Adaptive Optics for Extremely Large Telescopes) by J.L. Gach, D. Boutolleau, A. Caillat, P. Feautrier, R. Pourcelot, E. Stadler (LAM, First Light Imaging, IPAG)

Abstract: After releasing reference camera solutions in the visible and infrared for natural guide star wavefront sensing with unbeaten performance, we will present the first results of First Light Imaging’s C-MORE, the first laser guide star oriented wavefront sensor camera...

Visible and Near-infrared Laboratory Demonstration of a Simplified Pyramid Wavefront Sensor

April 2019 (Publications of the Astronomical Society of the Pacific, 131:044503 (9pp)) from Julien Lozi , Nemanja Jovanovic, Olivier Guyon, Mark Chun, Shane Jacobson, Sean Goebel, and Frantz Martinache

Abstract: Wavefront sensing and control are important for enabling one of the key advantages of using large apertures, namely higher angular resolution. Pyramid wavefront sensors are becoming commonplace in new instrument designs owing to their superior sensitivity. However, one remaining roadblock to their widespread use is the fabrication of the pyramidal optic. This complex optic is challenging to fabricate due to the pyramid tip, where four planes need to intersect at a single point.

MagAO-X: project status and first laboratory results

July 2018 (SPIE. 10703, Adaptive Optics Systems VI) Jared Males from Steward Observatory, University of Arizona, reports on his work with OCAM²K on the new Extreme Adaptive Optics instrument MagAO-X

Abstract: MagAO-X is an entirely new extreme adaptive optics system for the Magellan Clay 6.5 m telescope, funded by the NSF MRI program starting in Sep 2016. The key science goal of MagAO-X is high-contrast imaging of accreting protoplanets at Hα. With 2040 actuators operating at up to 3630 Hz, MagAO-X will deliver high Strehls (> 70%), high resolution (19 mas), and high contrast (< 1 × 10−4) at Hα (656 nm).

Design of the MagAO-X Pyramid Wavefront Sensor

July 2018 (SPIE 10703, Adaptive Optics Systems VI) Lauren H. Schatz from University of Arizona reports on her work with OCAM²K on the new extreme Adaptive Optics instrument MagAO-X

Abstract: Adaptive optics systems correct atmospheric turbulence in real time. Most adaptive optics systems used routinely correct in the near infrared, at wavelengths greater than 1 μm. MagAO- X is a new extreme adaptive optics (ExAO) instrument that will offer corrections at visible-to- near-IR wavelengths. MagAO-X will achieve Strehl ratios of ≥70% at Hα when running the 2040 actuator deformable mirror at 3.6 kHz. A visible pyramid wavefront sensor (PWFS) optimized for sensing at 600-1000 nm wavelengths will provide the high-order wavefront sensing on MagAO-X. We present the optical design and predicted performance of the MagAO-X pyramid wavefront sensor.

Photon counting in the Infrared with e-APD devices

June 2018 (10709-43 SPIE Astronomical Telescopes and Instrumentation) by Jean-Luc Gach (LAM, First Light Imaging)

Abstract: Since the first photon counting systems in the visible, developped by Boksenberg and his collabortors in 1972, many groups around the world improved photon counting techniques. In the 2000’s in the visible, EMCCDSs (electron multiplying charge coupled devices) allowed to replace the classical image intensifier photon counting systems by solid state devices and improved a lot the QE...

C-RED 2 InGaAs 640x512 600 fps infrared camera for low order wavefront sensing

June 2018 (10703-68 SPIE Astronomical Telescopes and Instrumentation) by P.Feautrier, JL.Gach et al. (First Light Imaging, IPAG, LAM)

Abstract: Infrared wavefront sensors are now implemented in MCAO systems as reference (or truth sensors). After the successful development of C-RED One, the only commercial 320x256 3500 fps e-APD sub-e noise infrared camera, First Light Imaging developed the C-RED 2 InGaAs 640x512 fast camera with unprecedented performances in terms of noise, dark and readout speed based on the SNAKE SWIR detector from Sofradir. The C-RED 2 characteristics and performances at 600 fps are fully described in this paper...

C-RED One and C-RED2: SWIR high-performance cameras using Saphira e-APD and Snake InGaAs detector

January 2018 (10539-41 SPIE Photonics West) by JL.Gach, P.Feautrier et al. (First Light Imaging, LAM, IPAG)

Abstract: After the development of the OCAM² EMCCD fast visible camera [1] dedicated to advanced adaptive optics wavefront sensing, First Light Imaging moved to the SWIR fast cameras with the development of the C-RED One and the C-RED 2 cameras. First Light Imaging’s C-RED One infrared camera is capable of capturing up to 3500 full frames per second with a subelectron readout noise and very low background. C-RED One is based on the last version of the SAPHIRA detector...

Infrared detectors for wavefront sensing

June 2017 (AO4ELT 5 – Adaptive Optics for Extremely Large Telescopes) by JL.Gach, P.Feautrier et al. (First Light Imaging, LAM, IPAG)

Abstract: After the development of the OCAM2 EMCCD fast visible camera [1] dedicated to advanced adaptive optics wavefront sensing, First Light Imaging moved to the SWIR fast cameras with the development of the C-RED One and the C-RED 2 cameras. First Light Imaging’s C-RED One infrared camera is capable of capturing up to 3500 full frames per second with a subelectron readout noise and very low background. C-RED One is based on the last version of the SAPHIRA detector...

C-RED One and C-RED 2: SWIR advanced cameras using Saphira e-APD and Snake InGaAs detectors

April 2017 (10209-15 SPIE Defense and Commercial Sensing) by Philippe Feautrier, Jean-Luc Gach et al. (First Light Imaging, IPAG, LAM)

Abstract: After the development of the OCAM2 EMCCD fast visible camera [1] dedicated to advanced adaptive optics wavefront sensing, First Light Imaging moved to the SWIR fast cameras with the C-RED One and the C-RED 2 cameras. These cameras and their performances are described extensively in this paper. First Light Imaging C-RED One infrared camera is capable of capturing up to 3500 full frames per second with subelectron readout noise and very low background. C-RED One is based on the last version of the SAPHIRA detector...

ADAPTIVE OPTICS FOR SATELLITE IMAGING AND EARTH BASED SPACE DEBRIS MANOEUVRES

April 2017 (SDC7-paper536 - 7th European Conference on Space Debris, ESA) report from Doris Grosse, Francis Bennet, Michael Copeland, Celine d’Orgeville, Francois Rigaut, and Ian Price (Australian National University, SERC)

Space Debris is becoming a more and more urgent issue and action needs to be taken to both actively reduce the amount of debris in space, and prevent space debris accumulation caused by collisions of existing debris. To investigate and mitigate the risk of collisions of space debris and satellites, a Cooperative Research Centre managed by the Space Environment Research Centre (SERC) has been established in Australia supported by the Australian government and national and international partners.

C-RED one: ultra-high speed wavefront sensing in the infrared made possible

June 2016 (9909-41 SPIE Astronomical Telescopes and Instrumentation) by Jean-Luc Gach, Philippe Feautrier, Eric Stadler et al. (First Light Imaging, IPAG, LAM, SELEX ES)

Abstract: First Light Imaging’s C-RED One infrared camera is capable of capturing up to 3500 full frames per second with a subelectron readout noise. This breakthrough has been made possible thanks to the use of an e-APD infrared focal plane array which is a real disruptive technology in imagery. We will show the performances of the camera, its main features and compare them to other high performance wavefront sensing cameras like OCAM2 in the visible and in the infrared...

C-RED One: The InfraRed Camera using the Saphira e-APD detector

June 2016 (9907-86 SPIE Astronomical Telescopes and Instrumentation) by Timothee Greffe et al., First Light Imaging

Abstract: First Light Imaging’s C-RED One infrared camera is capable of capturing up to 3500 full frames per second with a subelectron readout noise and very low background. This breakthrough has been made possible thanks to the use of an e-APD infrared focal plane array which is a real disruptive technology in imagery. C-RED One is an autonomous system with an integrated cooling system and a vacuum regeneration system.

C-RED One: The InfraRed Camera using the Saphira e-APD detector (Poster)

June 2016 (9907-86 SPIE Astronomical Telescopes and Instrumentation) by Timothee Greffe et al. (First Light Imaging)

Abstract: Developed by First Light Imaging and based on the Saphira HgCdTe APD detector from Selex, C-RED One is the only commercial infrared camera offering the new ADP (Avalanche Photo Diodes) disruptive technology in the area of infrared detectors...

Fast sub-electron detectors review for interferometry

June 2016 (9907-39 SPIE Astronomical Telescopes and Instrumentation) from P.Feautrier, JL.Gach and P.. Berio (IPAG, LAM, First Light Imaging, Laboratoire Lagrange)

Abstract: New disruptive technologies are now emerging for detectors dedicated to interferometry. The detectors needed for this kind of applications need antonymic characteristics: the detector noise must be very low, especially when the signal is dispersed but at the same time must also sample the fast temporal characteristics of the signal. This paper describes the new fast low noise technologies that have been recently developed for interferometry and adaptive optics.

OCAM2S: an integral shutter ultrafast and low noise wavefront sensor camera for laser guide stars adaptive optics systems

October 2015 (Preprints of the AO4ELT 4 Proceedings - Lake Arrowhead 2017) from JL.Gach, P.Feautrier et al.

Abstract: To date, the OCAM2 system has demonstrated to be the fastest and lowest noise production ready wavefront sensor, achieving 2067 full frames per second with subelectron readout noise. This makes OCAM2 the ideal system for natural as well as continuous wave laser guide star wavefront sensing. In this paper we present the new gated version of OCAM2 named OCAM2-S, using E2V’s CCD219 sensor with integral shutter…

State of the art IR cameras for wavefront sensing using e-APD MCT arrays

October 2015 (Preprints of the AO4ELT 4 Proceedings - Lake Arrowhead 2017)from P.Feautrier, JL.Gach and P. Wizinowich (IPAG, LAM, First Light Imaging and Keck Observatory)

Abstract: The recent discovery of electron initiated avalanche photodiodes (e-APDs) using mercury cadmium telluride semiconductor materials has permitted a significant advance in short-wave infrared imaging. In the visible spectrum, electron-multiplying charge-coupled devices (EMCCDs) improved imaging techniques—especially in the life sciences. And yet, no significant breakthroughs have been made in infrared imagery since the hybridization of III-V or II-VI semiconductors with low bandgap on complementary metal-oxide semiconductor (CMOS) read-out integrated circuits (ROICs)...

State of the art IR cameras for wavefront sensing using e-APD MCT arrays - China

September 2015 (Purple Mountain Observatory Chinese Academy of Sciences) P.Feautrier (IPAG, First Light Imaging)

Abstract: The success of the next generation of instrument for large (up to 10 m) or extremely larges telescopes (up to 40 m) in the visible-infrared will depend on the ability of Adaptive Optics (AO) systems to provide excellent image quality and stability. This will be achieved by increasing the sampling and correction of the wave front error in both spatial and time domains. For example, advanced Shack Hartmann systems currently fabricated require 40x40 sub-apertures at sampling rates of 1-1.5 kHz as opposed to 14x14 sub-apertures at 500 Hz of previous AO systems...

The Subaru Coronographic Extreme Adaptive Optics system: enabling high-contrast imaging on solar-system scales

October 2014 (Submitted to the Proceedings of the Astronomical Society of the Pacific) from N. Jovanovic, F. Martinache, O. Guyon et al.

Abstract: The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is a multipurpose high contrast-imaging platform designed for the discovery and detailed characterization of exoplanetary systems and serves as a testbed for instrumentation for ELTs…

OCAM2S: an integral shutter ultrafast and low noise wavefront sensor camera for laser guide stars adaptive optics systems

July 2014 (9148-44-v2 SPIE Astronomical Telescopes and Instrumentation - Montreal) Report from LAM (Laboratoire d'Astrophysique de Marseille)

Abstract: To date, the OCAM2 system has demonstrated to be the fastest and lowest noise production ready wavefront sensor, achieving 2067 full frames per second with subelectron readout noise. This makes OCAM2 the ideal system for natural as well as continuous wave laser guide star wavefront sensing. In this paper we present the new gated version of OCAM2 named OCAM2-S, using E2V’s CCD219 sensor with integral shutter…

Adaptive Optics for space debris tracking

July 2014 (91481F-1 SPIE Astronomical Telescopes and Instrumentation - Montreal) Report from Francis Bennet, Celine D’Orgeville, Yue Gao, William Gardhouse, Nicolas Paulin, et al.(Australian National University, EOS Space Systems)

Abstract: Space debris in Low Earth Orbit (LEO) is becoming an increasing threat to satellite and spacecraft. A reliable and cost effective method for detecting possible collisions between orbiting objects is required to prevent an exponential growth in the number of debris. Current RADAR survey technologies used to monitor the orbits of thousands of space debris objects are relied upon to manoeuvre operational satellites to prevent possible collisions...

High speed and High precision pyramid wavefront sensor - In labs validation and preparation to on sky demonstration

February 2014 (SPIE_2014_Paper_9148_208 - SPIE Astronomical Telescopes and Instrumentation - Montreal) Kacem El Hadi reports on his work with OCAM²

Abstract: Since the introduction of the pyramid wavefront sensor [P-WFS] concept (Ragazzoni), numerous investigations have clearly shown its ability to achieve better performance (sensitivity, dynamic range) than the standard Shack-Hartman [SH-WFS]...

Development of a Pyramid Wavefront Sensor

May 2013 (AO4ELT 3 - Florence, Italy) Kacem El Hadi from LAM  

Abstract: Within the framework of the E-ELT studies, several laboratories are involved on some instruments: ARMONI with its ATLAS adaptive optics [AO] system, EAGLE or EPICS. Most of the AO systems will probably integrate one or several pyramidal wavefront sensors, PWFS (R. Ragazzoni [1-2]). The coupling in an AO loop and the control in laboratory (then on sky) of this type of sensor is fundamental for the continuation of the projects related to OA systems on the E-ELT…

Visible and Infrared Wavefront Sensing detectors review in Europe – part I

May 2013 (AO4ELT 3 - Florence, Italy) P.Feautrier and JL.Gach (IPAG, First Light Imaging, LAM)  

Abstract. Within the framework of the E-ELT studies, several laboratories are involved on some instruments: ARMONI with its ATLAS adaptive optics [AO] system, EAGLE or EPICS. Most of the AO systems will probably integrate one or several pyramidal wavefront sensors, PWFS (R. Ragazzoni [1-2]). The coupling in an AO loop and the control in laboratory (then on sky) of this type of sensor is fundamental for the continuation of the projects related to OA systems on the E-ELT…

New wavefront sensing concepts for Adaptative Optics instrumentation

October 2012 (SPIE_2012_Paper_8535_16 - SPIE Astronomical Telescopes and Instrumentation - Amsterdam) Kacem El Hadi reports on his work with OCAM²

Abstract: For the last few years, Laboratory of Astrophysics of Marseille has been carrying out several R&D activities in Adaptive Optics (AO) instrumentation for Extremely Large Telescopes (ELTs). In the European ELT(D = 40 m) framework, both theoretical and experimental studies are jointly led...

Toward an experimental validation of new AO concepts for future E-ELT instrumentation

July 2012 (SPIE_2012_Paper_8447-184 - SPIE Astronomical Telescopes and Instrumentation - Amsterdam) Kacem El Hadi reports on his work with OCAM²  

Abstract: For the last few years, LAM has been carrying out several R&D activities in Adaptive Optics (AO) instrumentation for Extremely Large Telescopes(ELTs). In the European ELT framework, a multi-purpose AO bench is developed to allow the experimental validation of new instrumental concepts dedicated to the next generation of ELTs...

Advances in Detector Technologies for Visible and Infrared Wavefront Sensing

July 2012 (Feautrier_8447-26-preprint SPIE Astronomical Telescopes and Instrumentation - Amsterdam) Feautrier, Gach et al.  

Abstract: The purpose of this paper is to give an overview of the state of the art wavefront sensor detectors developments held in Europe for the last decade. The success of the next generation of instruments for 8 to 40-m class telescopes will depend on the ability of Adaptive Optics (AO) systems to provide excellent image quality and stability...

OCAM with CCD220, the Fastest and Most Sensitive Camera to Date for AO Wavefront Sensing

March 2011 (Publication of the Astronomical Society of the Pacific 123:263–274) by Feautrier, Gach et al.

Abstract: For the first time, subelectron readout noise has been achieved with a camera dedicated to astronomical wavefront-sensing applications. The OCam system demonstrated this performance at a 1300 Hz frame rate and with 240 × 240 pixel frame size. ESO and JRA2 OPTICON jointly funded e2v Technologies to develop a custom CCD for adaptive optics (AO) wavefront-sensing applications. The device, called CCD220, is a compact Peltier-cooled 240 × 240 pixel frame-transfer eight-output back-illuminated sensor using the EMCCD technology...

Characterization of OCAM and CCD220, the fastest and most sensitive camera to date for AO wavefront sensing

June 2010 (Feautrier_8447-26-preprint SPIE Astronomical Telescopes and Instrumentation - San Diego)

For the first time, sub-electron read noise has been achieved with a camera suitable for astronomical wavefront-sensing (WFS) applications. The OCam system has demonstrated this performance at 1300 Hz frame rate and with 240x240-pixel frame rate. ESO and JRA2 OPTICON2 have jointly funded e2v technologies to develop a custom CCD for Adaptive Optics (AO) wavefront sensing applications...