Jean-Luc Gach

Jean-Luc Gach
Aix-Marseille Université | AMU · Laboratory of Astrophysics of Marseille (UMR 7326 LAM)

PhD & Master's in engineering

About

128
Publications
14,590
Reads
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1,798
Citations
Citations since 2016
54 Research Items
877 Citations
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Introduction
Jean-Luc Gach currently works at the Laboratory of Astrophysics of Marseille (UMR 7326 LAM), Aix-Marseille Université. Jean-Luc does research detector technologies (visible and infrared imagers) and Astronomy. Their current project is 'C-Red one'.
Education
January 2018 - April 2018
Aix-Marseille Université
Field of study
  • instrumentation
September 1994 - June 1995
September 1989 - June 1994
Institut National des Sciences Appliquées de Lyon
Field of study
  • Electrical Engineering

Publications

Publications (128)
Conference Paper
Full-text available
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 de...
Preprint
Full-text available
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. Within the Opticon WP2 european funded project (INFRAIA 2016-2017, Grant agreement...
Conference Paper
HARMONI is the first light, adaptive optics assisted, integral field spectrograph for the European Southern Observatory’s Extremely Large Telescope (ELT). A work-horse instrument, it provides the ELT’s diffraction limited spectroscopic capability across the near-infrared wavelength range. HARMONI will exploit the ELT’s unique combination of exquisi...
Preprint
Full-text available
We present here the latest results obtained with the C-RED One camera developed by First Light Imaging for fast ultra-low 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 im...
Preprint
Full-text available
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) h...
Preprint
Full-text available
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 EL...
Preprint
Full-text available
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 t...
Article
Full-text available
Using the VESTIGE survey, a deep narrow-band H α imaging survey of the Virgo cluster carried out at the CFHT with MegaCam, we discovered a long and diffuse tail of ionised gas in the edge-on late-type galaxy NGC 4330. This peculiar feature indicates an ongoing ram pressure stripping event able to remove the gas in the outer region of the disc. Tune...
Preprint
Full-text available
Using the VESTIGE survey, a deep narrow-band H$\alpha$ imaging survey of the Virgo cluster carried on at the CFHT with MegaCam, we discovered a long diffuse tail of ionised gas in the edge-on late-type galaxy NGC 4330. This peculiar feature witnesses an ongoing ram pressure stripping (RPS) event able to remove the gas in the outer disc region. Tune...
Article
Full-text available
Context. Laser guide stars (LGS) allow adaptive optics (AO) systems to reach greater sky coverage, especially for AO systems correcting the atmospheric turbulence on large fields of view. However LGS suffer from limitations, among which is their apparent elongation which can reach 20 arcsec when observed with large aperture telescopes such as the E...
Conference Paper
Full-text available
HARMONI is the adaptive optics assisted, near-infrared and visible light integral field spectrograph for the Extremely Large Telescope (ELT). A first light instrument, it provides the work-horse spectroscopic capability for the ELT. As the project approaches its Final Design Review milestone, the design of the instrument is being finalized, and the...
Preprint
Full-text available
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 de...
Article
Full-text available
Aims. We present new 2D high resolution Fabry–Perot spectroscopic observations of 152 star-forming galaxies that are part of the Herschel Reference Survey (HRS), which is a complete K -band selected, volume-limited sample of nearby galaxies that spans a wide range of stellar mass and morphological types. Methods. By using improved data reduction te...
Preprint
Full-text available
We present new 2D high resolution Fabry-Perot spectroscopic observations of 152 star-forming galaxies which are part of the $Herschel$ Reference Survey (HRS), a complete $K$-band selected, volume-limited sample of nearby galaxies, spanning a wide range in stellar mass and morphological type. Using improved data reduction techniques that provide ada...
Conference Paper
Full-text available
The emergence of curved sensors technologies opens a new way to design compact high-performance optical systems. Recent progress on the French activity on curved sensors are presented in terms of optical performance and experimental results. The existing prototypes are demonstrated at TRL4, for VIS and SWIR domains. We present the roadmap jointly d...
Preprint
Full-text available
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...
Preprint
Full-text available
a First Light Imaging S.A.S. 100, Route des houillères, 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 w...
Conference Paper
Full-text available
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 s...
Conference Paper
Full-text available
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 s...
Poster
Full-text available
Wavefront sensing detectors: 2 decades of technological progress
Conference Paper
Full-text available
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 capabl...
Article
Full-text available
The performance of adaptive optics systems is partially dependant on the algorithms used within the real-time control system to compute wavefront slope measurements. We demonstrate use of a matched filter algorithm for the processing of elongated laser guide star (LGS) Shack-Hartmann images, using the CANARY adaptive optics instrument on the 4.2 m...
Patent
Full-text available
Conference Paper
Full-text available
The success of the next generation of instruments for ELT class telescopes will depend upon improving the image quality by exploiting sophisticated Adaptive Optics (AO) systems. One of the critical components of the AO systems for the European Extremely Large Telescope (E-ELT) has been identified as the Large Visible Laser/Natural Guide Star AO Wav...
Conference Paper
Innovative optical designs allow tackling the spot elongation issues in Shack-Hartman based laser guide star wavefront sensors. We propose two solutions using either a combination of two arrays of freeform microlenses, or a combination of freeform optics, to perform a shrinkage of the laser spots as well as a magnification of the SH focal plane. Th...
Conference Paper
Full-text available
This paper presents the design and the realisation of a technique to attenuate the hysteresis nonlinear phenomenon of piezoelectric actuators. Piezoelectric actuator are widely utilised for deformable mirrors used for MOAO and power laser beam shaping techniques. The nonlinearities of piezo are usually iteratively compensa- ted using closed-loop se...
Conference Paper
Full-text available
First Light Imaging's CRED-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...
Conference Paper
Full-text available
HARMONI is a visible and NIR integral field spectrograph, providing the E-ELT’s core spectroscopic capability at first light. HARMONI will work at the diffraction limit of the E-ELT, thanks to a Classical and a Laser Tomographic AO system. In this paper, we present the system choices that have been made for these SCAO and LTAO modules. In particula...
Conference Paper
CANARY is an on-sky Laser Guide Star (LGS) tomographic AO demonstrator in operation at the 4.2m William Herschel Telescope (WHT) in La Palma. From the early demonstration of open-loop tomography on a single deformable mirror using natural guide stars in 2010, CANARY has been progressively upgraded each year to reach its final goal in July 2015. It...
Article
Full-text available
Recent advances in adaptive optics (AO) have led to the implementation of wide field-of-view AO systems. A number of wide-field AO systems are also planned for the forthcoming Extremely Large Telescopes. Such systems have multiple wavefront sensors of different types, and usually multiple deformable mirrors (DMs). Here, we report on our experience...
Conference Paper
CANARY is an on-sky demonstrator instrument for the investigation of novel forms of tomographic Adaptive Optics (AO) which are required by the prospective European Extremely Large Telescope (E-ELT). CANARY is deployed on the 4.2m William Herschel Telescope in the Canary Islands, Spain. In its most evolved variant (Phase C2), CANARY employs four Las...
Article
Full-text available
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.
Conference Paper
The RAPID camera is an Avalanche Photo Diode array allowing very fast observation from the optical to the infrared with still a low noise per read. The camera born from a large collaboration within the FUI/FOCUS is intensively tested at IPAG (Grenoble) on an interferometric bench and will soon replace the actual camera of the PIONIER interferometer...
Conference Paper
In the next 2 or 3 years, the two major interferometric arrays, VLTI and CHARA, will equip their telescopes of 1.8m and 1m respectively with Adaptive Optics (AO hereafter) systems. This improvement will permit to apply with a reasonable e_ciency in the visible domain, the principle of spatial filtering with single mode fibers demonstrated in the ne...
Conference Paper
Full-text available
The success of the next generation of instruments for ELT class telescopes will depend upon improving the image quality by exploiting sophisticated Adaptive Optics (AO) systems. One of the critical components of the AO systems for the E-ELT has been identified as the optical Laser/Natural Guide Star WFS detector. The combination of large format, 17...