ORCID Profile
0000-0002-0989-9302
Current Organisations
KU Leuven
,
University of Sydney
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Publisher: SPIE
Date: 13-12-2020
DOI: 10.1117/12.2562832
Publisher: Cambridge University Press (CUP)
Date: 2021
DOI: 10.1017/PASA.2021.29
Abstract: In 1978, Bracewell suggested the technique of nulling interferometry to directly image exoplanets which would enable characterisation of their surfaces, atmospheres, weather, and possibly determine their capacity to host life. The contrast needed to discriminate starlight reflected by a terrestrial-type planet from the glare of its host star lies at or beyond a forbidding $10^{-10}$ for an exo-Earth in the habitable zone around a Sun-like star at near-infrared wavelengths, necessitating instrumentation with extremely precise control of the light. Guided Light Interferometric Nulling Technology (GLINT) is a testbed for new photonic devices conceived to overcome the challenges posed by nulling interferometry. At its heart, GLINT employs a single-mode nulling photonic chip fabricated by direct-write technology to coherently combine starlight from an arbitrarily large telescope at 1 550 nm. It operates in combination with an actuated segmented mirror in a closed-loop control system, to produce and sustain a deep null throughout observations. The GLINT South prototype interface s the 3.9-m Anglo-Australian Telescope and was tested on a s le of bright Mira variable stars. Successful and continuous starlight injection into the photonic chip was achieved. A statistical model of the data was constructed, enabling a data reduction algorithm to retrieve contrast ratios of about $10^{-3}$ . As a byproduct of this analysis, stellar angular diameters that were below the telescope diffraction limit ( $\\sim$ 100 mas) were recovered with 1 $\\sigma$ accuracy and shown to be in agreement with literature values despite working in the seeing-limited regime. GLINT South serves as a demonstration of the capability of direct-write photonic technology for achieving coherent, stable nulling of starlight, which will encourage further technological developments towards the goal of directly imaging exoplanets with future large ground based and space telescopes.
Publisher: SPIE
Date: 09-08-2021
DOI: 10.1117/12.2602859
Publisher: SPIE
Date: 26-08-2022
DOI: 10.1117/12.2627939
Publisher: EDP Sciences
Date: 10-2018
DOI: 10.1051/0004-6361/201731386
Abstract: Aims. In the context of the future developments of long baseline interferometry at visible wavelengths, we have built a prototype instrument called Fibered spectrally Resolved Interferometer – New Design (FRIEND) based on single mode fibers and a new generation detector called Electron Multiplying Charge-Coupled Device (EMCCD). Installed on the Center for High Angular Resolution Astronomy (CHARA) array, it aims to estimate the performance of a fibered instrument in the visible when coupled with telescopes equipped with adaptive optics (AO) in partial correction. Methods. We observed different sequences of targets and reference stars to study the compensation of the birefringence of the fibers, the coupling efficiency in various conditions of correction, and to calibrate our numerical model of signal-to-noise ratio (S/N). We also used a known binary star to demonstrate the reliability and the precision of our squared visibility and closure phase measurements. Results. We firstly present a reliable and stable solution for compensating the birefringence of the fibers with an improvement of a factor of 1.5 of the instrumental visibility. We then demonstrate an improvement by a factor of between 2.5 and 3 of the coupling efficiency when using the LABAO systems in closed loop. The third results of our paper is the demonstration of the correct calibration of the parameters of our S/N estimator provided the correct excess noise factor of EMCCD is correctly taken into account. Finally with the measurements of the angular separation, difference of magnitude and in idual diameters of the two components of ζ Ori A, we demonstrate the reliability and precision of our interferometric estimators, and in particular a median residual on the closure phase of 1.2°.
Publisher: SPIE
Date: 30-08-2022
DOI: 10.1117/12.2630503
Publisher: SPIE
Date: 03-01-2020
DOI: 10.1117/12.2539790
Publisher: SPIE
Date: 13-12-2020
DOI: 10.1117/12.2561505
Publisher: Optica Publishing Group
Date: 17-06-2021
DOI: 10.1364/AO.423541
Abstract: Integrated-optic components are being increasingly used in astrophysics, mainly where accuracy and precision are paramount. One such emerging technology is nulling interferometry that targets high contrast and high angular resolution. Two of the most critical limitations encountered by nullers are rapid phase fluctuations in the incoming light causing instability in the interference and chromaticity of the directional couplers that prevent a deep broadband interferometric null. We explore the use of a tricoupler designed by ultrafast laser inscription that solves both issues. Simulations of a tricoupler, incorporated into a nuller, result in an order of a magnitude improvement in null depth.
Publisher: Oxford University Press (OUP)
Date: 23-11-2020
Abstract: The characterization of exoplanets is critical to understanding planet ersity and formation, their atmospheric composition, and the potential for life. This endeavour is greatly enhanced when light from the planet can be spatially separated from that of the host star. One potential method is nulling interferometry, where the contaminating starlight is removed via destructive interference. The GLINT instrument is a photonic nulling interferometer with novel capabilities that has now been demonstrated in on-sky testing. The instrument fragments the telescope pupil into sub-apertures that are injected into waveguides within a single-mode photonic chip. Here, all requisite beam splitting, routing, and recombination are performed using integrated photonic components. We describe the design, construction, and laboratory testing of our GLINT pathfinder instrument. We then demonstrate the efficacy of this method on sky at the Subaru Telescope, achieving a null-depth precision on sky of ∼10−4 and successfully determining the angular diameter of stars (via their null-depth measurements) to milliarcsecond accuracy. A statistical method for analysing such data is described, along with an outline of the next steps required to deploy this technique for cutting-edge science.
Publisher: SPIE
Date: 13-12-2020
DOI: 10.1117/12.2560857
Publisher: SPIE
Date: 09-07-2018
DOI: 10.1117/12.2311869
Publisher: SPIE-Intl Soc Optical Eng
Date: 27-06-2023
Publisher: SPIE
Date: 09-2021
DOI: 10.1117/12.2594840
Publisher: SPIE
Date: 09-2021
DOI: 10.1117/12.2594885
Publisher: SPIE
Date: 26-08-2022
DOI: 10.1117/12.2628151
Publisher: SPIE
Date: 04-08-2016
DOI: 10.1117/12.2231704
Publisher: Optica Publishing Group
Date: 2020
DOI: 10.1364/CLEOPR.2020.C7G_2
Abstract: Imaging exoplanets requires high angular resolution and high contrast capability. Nulling interferometry with integrated-photonics technology can address these challenges. This paper presents GLINT, a nulling interferometer based on photonic technologies and its first on-sky results.
Publisher: SPIE
Date: 26-08-2022
DOI: 10.1117/12.2627942
Publisher: The Optical Society
Date: 03-04-2017
Publisher: SPIE
Date: 13-12-2020
DOI: 10.1117/12.2562723
Publisher: Springer Science and Business Media LLC
Date: 12-2018
Publisher: SPIE
Date: 26-08-2022
DOI: 10.1117/12.2629873
Publisher: SPIE
Date: 26-08-2022
DOI: 10.1117/12.2628268
Publisher: Springer Science and Business Media LLC
Date: 29-04-2021
DOI: 10.1038/S41467-021-22769-X
Abstract: Characterisation of exoplanets is key to understanding their formation, composition and potential for life. Nulling interferometry, combined with extreme adaptive optics, is among the most promising techniques to advance this goal. We present an integrated-optic nuller whose design is directly scalable to future science-ready interferometric nullers: the Guided-Light Interferometric Nulling Technology, deployed at the Subaru Telescope. It combines four beams and delivers spatial and spectral information. We demonstrate the capability of the instrument, achieving a null depth better than 10 −3 with a precision of 10 −4 for all baselines, in laboratory conditions with simulated seeing applied. On sky, the instrument delivered angular diameter measurements of stars that were 2.5 times smaller than the diffraction limit of the telescope. These successes pave the way for future design enhancements: scaling to more baselines, improved photonic component and handling low-order atmospheric aberration within the instrument, all of which will contribute to enhance sensitivity and precision.
Publisher: SPIE-Intl Soc Optical Eng
Date: 22-10-2022
Publisher: SPIE
Date: 26-08-2022
DOI: 10.1117/12.2627978
Publisher: SPIE
Date: 13-12-2020
DOI: 10.1117/12.2562792
Publisher: EDP Sciences
Date: 03-2023
DOI: 10.1051/0004-6361/202244351
Abstract: Context . NOTT (formerly Hi-5) is a new high-contrast L ′ band (3.5–4.0 µm) beam combiner for the VLTI designed with an ambitious aim to be sensitive to young giant exoplanets down to 5 mas separation around nearby stars. The performance of nulling interferometers in these wavelengths is affected both by fundamental noise from the background and contributions of instrumental noise. This motivates the development of end-to-end simulations to optimize these instruments. Aims . The aim of this study is to enable a performance evaluation of NOTT and inform the design of such instruments with current and future infrastructures in mind, taking into account the different sources of noise and their correlation. Methods . SCIFYsim is an end-to-end simulator for single-mode-filtered beam combiners, with an emphasis on nulling interferometers. We use it to compute a covariance matrix of the errors. We then use statistical detection tests based on likelihood ratios to compute compound detection limits for the instrument. Results . With the current assumptions as to the performance of the wavefront correction systems, the errors are dominated by correlated instrumental errors down to stars of magnitude 6–7 in the L band, beyond which thermal background from the telescopes and relay system becomes dominant. Conclusions . SCIFYsim is suited to anticipating some of the challenges of design, tuning, operation, and signal processing for integrated-optics beam combiners. The detection limits found for this early version of NOTT simulation with the unit telescopes are compatible with detections at contrasts up to 10 5 in the L band at separations of 5–80 mas around bright stars.
Publisher: SPIE
Date: 26-08-2022
DOI: 10.1117/12.2627973
Publisher: IOP Publishing
Date: 10-2023
Abstract: Photonic technologies offer numerous functionalities that can be used to realize astrophotonic instruments. The most spectacular ex le to date is the ESO Gravity instrument at the Very Large Telescope in Chile that combines the light-gathering power of four 8-m telescopes through a complex photonic interferometer. Fully integrated astrophotonic devices offer critical advantages for instrument development, including extreme miniaturization when operating at the diffraction-limit, plus integration, superior thermal and mechanical stabilization owing to the small footprint, and high replicability offering significant cost savings. Numerous astrophotonic technologies have been developed to address shortcomings of conventional instruments to date, including the development of photonic lanterns to convert from multimode inputs to single mode outputs, complex aperiodic fiber Bragg gratings to filter OH emission from the atmosphere, beam combiners enabling long baseline interferometry with for ex le, ESO Gravity, and laser frequency combs for high precision spectral calibration of spectrometers. Despite these successes, the facility implementation of photonic solutions in astronomical instrumentation is currently limited because of 1) low throughputs from coupling to fibers, coupling fibers to chips, propagation and bend losses, device losses, etc., 2) difficulties with scaling to large channel count devices needed for large bandwidths and high resolutions, and 3) efficient integration of photonics with detectors. In this roadmap, we identify 23 key areas that need further development. We outline the challenges and advances needed across those areas covering design tools, simulation capabilities, fabrication processes, the need for entirely new components, integration and hybridization and the characterization of devices. To realize these advances the astrophotonics community will have to work cooperatively with industrial partners who have more advanced manufacturing capabilities. With the advances described herein, multi-functional integrated instruments will be realized leading to novel observing capabilities for both ground and space based platforms, enabling new scientific studies and discoveries.
Publisher: SPIE
Date: 26-08-2022
DOI: 10.1117/12.2627953
No related grants have been discovered for Marc-Antoine Martinod.