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1. E-TEST prototype design report

Author

Sider, A., Amez-Droz, L., Amorosi, A., Badaracco, F., Baer, P., Bruno, G., Bertolini, A., Collette, C., Cebeci, P., Di Fronzo, C., Ebert, J., Erben, B., Esteves, R., Ferreira, E., Gatti, A., Giesberts, M., Hebbeker, T., Hennig, J. S., Hennig, M., Hild, S., Hoefer, M., Hoffmann, H. D., Jacques, L., Jamshidi, R., Joppe, R., Kuhlbusch, T., Lenaert, C., Lakkis, M. H., Van, B. L. Le, Loicq, J., Locquet, J. P., Loosen, P., Nesladek, M., Reiter, M., Stahl, A., Steinlechner, J., Steinlechner, S., Teloi, M., Perez, J. Villaboa, van Heijningen, J., and Zeoli, M.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, General Relativity and Quantum Cosmology
Abstract

E-TEST (Einstein Telescope Euregio-Meuse-Rhin Site and Technology) is a project recently funded by the European program Ineterreg Euregio Meuse-Rhine. This program is dedicated to innovative cross boarder activities between Belgium, The Netherlands and Germany. With a total budget of15MC and a consortium of 11 partners from the three countries, the objective of the project is twofold. Firstly, to develop an eco-friendly and non-invasive imaging of the geological conditions as well as the development of an observatory of the underground in the EMR region. Secondly, to develop technologies necessary for 3rd generation gravitational wave detectors. In particular, it is proposed to develop a prototype of large suspended cryogenic silicon mirror, isolated from seismic vibrations at low frequency. The total budget of the project is equally spread over the two activities. The first activity is not discussed at all in this report. The E-TEST prototype will have some key unique features: a silicon mirror of 100 kg, a radiative cooling strategy (non contact), a low-frequency hybrid isolation stage, cryogenic sensors and electronics, a laser and optics at 2 microns, a low thermal noise coating.

Published
2022

2. Large Interferometer For Exoplanets (LIFE)

Author

Quanz, SP, Ottiger, M, Fontanet, E, Kammerer, J, Menti, F, Dannert, F, Gheorghe, A, Absil, O, Airapetian, VS, Alei, E, Allart, R, Angerhausen, D, Blumenthal, S, Buchhave, LA, Cabrera, J, Carrión-González, Ó, Chauvin, G, Danchi, WC, Dandumont, C, Defrére, D, Dorn, C, Ehrenreich, D, Ertel, S, Fridlund, M, Muñoz, A García, Gascón, C, Girard, JH, Glauser, A, Grenfell, JL, Guidi, G, Hagelberg, J, Helled, R, Ireland, MJ, Janson, M, Kopparapu, RK, Korth, J, Kozakis, T, Kraus, S, Léger, A, Leedjärv, L, Lichtenberg, T, Lillo-Box, J, Linz, H, Liseau, R, Loicq, J, Mahendra, V, Malbet, F, Mathew, J, Mennesson, B, Meyer, MR, Mishra, L, Molaverdikhani, K, Noack, L, Oza, AV, Pallé, E, Parviainen, H, Quirrenbach, A, Rauer, H, Ribas, I, Rice, M, Romagnolo, A, Rugheimer, S, Schwieterman, EW, Serabyn, E, Sharma, S, Stassun, KG, Szulágyi, J, Wang, HS, Wunderlich, F, and Wyatt, MC

Subjects
planets and satellites, terrestrial planets, telescopes, instrumentation, high angular resolution, methods, numerical, detection, infrared, planetary systems, Astronomical and Space Sciences, Astronomy & Astrophysics
Abstract

Context. One of the long-term goals of exoplanet science is the atmospheric characterization of dozens of small exoplanets in order to understand their diversity and search for habitable worlds and potential biosignatures. Achieving this goal requires a space mission of sufficient scale that can spatially separate the signals from exoplanets and their host stars and thus directly scrutinize the exoplanets and their atmospheres.Aims. We seek to quantify the exoplanet detection performance of a space-based mid-infrared (MIR) nulling interferometer that measures the thermal emission of exoplanets. We study the impact of various parameters and compare the performance with that of large single-aperture mission concepts that detect exoplanets in reflected light.Methods. We have developed an instrument simulator that considers all major astrophysical noise sources and coupled it with Monte Carlo simulations of a synthetic exoplanet population around main-sequence stars within 20 pc of the Sun. This allows us to quantify the number (and types) of exoplanets that our mission concept could detect. Considering single visits only, we discuss two different scenarios for distributing 2.5 yr of an initial search phase among the stellar targets. Different apertures sizes and wavelength ranges are investigated.Results. An interferometer consisting of four 2 m apertures working in the 4–18.5 μ.m wavelength range with a total instrument throughput of 5% could detect up to ≈550 exoplanets with radii between 0.5 and 6 R⊕ with an integrated S/N ≥ 7. At least ≈160 of the detected exoplanets have radii ≤1.5 R⊕. Depending on the observing scenario, ≈25–45 rocky exoplanets (objects with radii between 0.5 and 1.5 R⊕) orbiting within the empirical habitable zone (eHZ) of their host stars are among the detections. With four 3.5 m apertures, the total number of detections can increase to up to ≈770, including ≈60–80 rocky eHZ planets. With four times 1 m apertures, the maximum detection yield is ≈315 exoplanets, including ≤20 rocky eHZ planets. The vast majority of small, temperate exoplanets are detected around M dwarfs. The impact of changing the wavelength range to 3–20 μm or 6–17 μm on the detection yield is negligible.Conclusions. A large space-based MIR nulling interferometer will be able to directly detect hundreds of small, nearby exoplanets, tens of which would be habitable world candidates. This shows that such a mission can compete with large single-aperture reflected light missions. Further increasing the number of habitable world candidates, in particular around solar-type stars, appears possible via the implementation of a multi-visit strategy during the search phase. The high median S/N of most of the detected planets will allow for first estimates of their radii and effective temperatures and will help prioritize the targets for a second mission phase to obtain high-S/N thermal emission spectra, leveraging the superior diagnostic power of the MIR regime compared to shorter wavelengths.

Published
2022

3. Large Interferometer For Exoplanets (LIFE): I. Improved exoplanet detection yield estimates for a large mid-infrared space-interferometer mission

Author

Quanz, S. P., Ottiger, M., Fontanet, E., Kammerer, J., Menti, F., Dannert, F., Gheorghe, A., Absil, O., Airapetian, V. S., Alei, E., Allart, R., Angerhausen, D., Blumenthal, S., Buchhave, L. A., Cabrera, J., Carrión-González, Ó., Chauvin, G., Danchi, W. C., Dandumont, C., Defrère, D., Dorn, C., Ehrenreich, D., Ertel, S., Fridlund, M., Muñoz, A. García, Gascón, C., Girard, J. H., Glauser, A., Grenfell, J. L., Guidi, G., Hagelberg, J., Helled, R., Ireland, M. J., Janson, M., Kopparapu, R. K., Korth, J., Kozakis, T., Kraus, S., Léger, A., Leedjärv, L., Lichtenberg, T., Lillo-Box, J., Linz, H., Liseau, R., Loicq, J., Mahendra, V., Malbet, F., Mathew, J., Mennesson, B., Meyer, M. R., Mishra, L., Molaverdikhani, K., Noack, L., Oza, A. V., Pallé, E., Parviainen, H., Quirrenbach, A., Rauer, H., Ribas, I., Rice, M., Romagnolo, A., Rugheimer, S., Schwieterman, E. W., Serabyn, E., Sharma, S., Stassun, K. G., Szulágyi, J., Wang, H. S., Wunderlich, F., Wyatt, M. C., and collaboration, the LIFE

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

One of the long-term goals of exoplanet science is the atmospheric characterization of dozens of small exoplanets in order to understand their diversity and search for habitable worlds and potential biosignatures. Achieving this goal requires a space mission of sufficient scale. We seek to quantify the exoplanet detection performance of a space-based mid-infrared nulling interferometer that measures the thermal emission of exoplanets. For this, we have developed an instrument simulator that considers all major astrophysical noise sources and coupled it with Monte Carlo simulations of a synthetic exoplanet population around main-sequence stars within 20 pc. This allows us to quantify the number (and types) of exoplanets that our mission concept could detect over a certain time period. Two different scenarios to distribute the observing time among the stellar targets are discussed and different apertures sizes and wavelength ranges are considered. Within a 2.5-year initial search phase, an interferometer consisting of four 2 m apertures with a total instrument throughput of 5% covering a wavelength range between 4 and 18.5 $\mu$m could detect up to ~550 exoplanets with radii between 0.5 and 6 R$_\oplus$ with an integrated SNR$\ge$7. At least ~160 of the detected exoplanets have radii $\le$1.5 R$_\oplus$. Depending on the observing scenario, ~25-45 rocky exoplanets (objects with radii between 0.5 and 1.5 $_{\oplus}$) orbiting within the empirical habitable zone (eHZ) of their host stars are among the detections. With an aperture size of 3.5 m, the total number of detections can increase to up to ~770, including ~60-80 rocky, eHZ planets. With 1 m aperture size, the maximum detection yield is ~315 exoplanets, including $\le$20 rocky, eHZ planets. In terms of predicted detection yield, such a mission can compete with large single-aperture reflected light missions. (abridged), Comment: Accepted for publication by A&A - some typos corrected and affiliations updated; 14 pages main text (incl. 14 figures); first paper in the LIFE paper series; papers II (arXiv:2203.00471) and III (arXiv:2112.02054) are also available

Published
2021
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4. Characterizing the atmosphere of Proxima b with a space-based mid-infrared nulling interferometer

Author

Defrère, D., Léger, A., Absil, O., Munoz, A. Garcia, Grenfell, J. L., Godolt, M., Loicq, J., Kammerer, J., Quanz, S., Rauer, H., Schifano, L., and Tian, F.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Proxima b is our nearest potentially rocky exoplanet and represents a formidable opportunity for exoplanet science and possibly astrobiology. With an angular separation of only 35~mas (or 0.05~AU) from its host star, Proxima b is however hardly observable with current imaging telescopes and future space-based coronagraphs. One way to separate the photons of the planet from those of its host star is to use an interferometer that can easily resolve such spatial scales. In addition, its proximity to Earth and its favorable contrast ratio compared with its host M dwarf (approximately 10$^{-5}$ at 10 microns) makes it an ideal target for a space-based nulling interferometer with relatively small apertures. In this paper, we present the motivation for observing this planet in the mid-infrared (5-20 microns) and the corresponding technological challenges. Then, we describe the concept of a space-based infrared interferometer with relatively small ($<$1m in diameter) apertures that can measure key details of Proxima b, such as its size, temperature, climate structure, as well as the presence of important atmospheric molecules such as H$_2$O, CO$_2$, O$_3$, and CH$_4$. Finally, we illustrate the concept by showing realistic observations using synthetic spectra of Proxima b computed with coupled climate chemistry models., Comment: 10 pages, 5 figures, SPIE Proceedings

Published
2018

5. The Far Ultra-Violet Imager on the Icon Mission

Author

Mende, SB, Frey, HU, Rider, K, Chou, C, Harris, SE, Siegmund, OHW, England, SL, Wilkins, C, Craig, W, Immel, TJ, Turin, P, Darling, N, Loicq, J, Blain, P, Syrstad, E, Thompson, B, Burt, R, Champagne, J, Sevilla, P, and Ellis, S

Subjects
Space Sciences, Astronomical Sciences, Physical Sciences, Space-borne far ultraviolet spectral imager, Imaging the Earth's atmosphere/ionosphere, Instrument for observing the upper atmosphere, Astronomical and Space Sciences, Astronomy & Astrophysics, Astronomical sciences, Space sciences
Abstract

ICON Far UltraViolet (FUV) imager contributes to the ICON science objectives by providing remote sensing measurements of the daytime and nighttime atmosphere/ionosphere. During sunlit atmospheric conditions, ICON FUV images the limb altitude profile in the shortwave (SW) band at 135.6 nm and the longwave (LW) band at 157 nm perpendicular to the satellite motion to retrieve the atmospheric O/N2 ratio. In conditions of atmospheric darkness, ICON FUV measures the 135.6 nm recombination emission of O+ ions used to compute the nighttime ionospheric altitude distribution. ICON Far UltraViolet (FUV) imager is a CzernyTurner design Spectrographic Imager with two exit slits and corresponding back imager cameras that produce two independent images in separate wavelength bands on two detectors. All observations will be processed as limb altitude profiles. In addition, the ionospheric 135.6 nm data will be processed as longitude and latitude spatial maps to obtain images of ion distributions around regions of equatorial spread F. The ICON FUV optic axis is pointed 20 degrees below local horizontal and has a steering mirror that allows the field of view to be steered up to 30 degrees forward and aft, to keep the local magnetic meridian in the field of view. The detectors are micro channel plate (MCP) intensified FUV tubes with the phosphor fiber-optically coupled to Charge Coupled Devices (CCDs). The dual stack MCP-s amplify the photoelectron signals to dominate the CCD noise and the rapidly scanned frames are co-added to digitally create 12-second integrated images. Digital on-board signal processing is used to compensate for geometric distortion and satellite motion and to achieve data compression. The instrument was originally aligned in visible light by using a special grating and visible cameras. Final alignment, functional and environmental testing and calibration were performed in a large vacuum chamber with a UV source. The test and calibration program showed that ICON FUV meets its design requirements and is ready to be launched on the ICON spacecraft.

Published
2017

6. E-TEST: a compact low-frequency isolator for a large cryogenic mirror

Author

Sider, A, primary, Di Fronzo, C, additional, Amez-Droz, L, additional, Amorosi, A, additional, Badaracco, F, additional, Baer, P, additional, Bertolini, A, additional, Bruno, G, additional, Cebeci, P, additional, Collette, C, additional, Ebert, J, additional, Erben, B, additional, Esteves, R, additional, Ferreira, E, additional, Gatti, A, additional, Giesberts, M, additional, Hebbeker, T, additional, van Heijningen, J V, additional, Hennig, J-S, additional, Hennig, M, additional, Hild, S, additional, Hoefer, M, additional, Hoffmann, H-D, additional, Jacques, L, additional, Jamshidi, R, additional, Joppe, R, additional, Kuhlbusch, T-J, additional, Lakkis, M H, additional, Lenaerts, C, additional, Locquet, J-P, additional, Loicq, J, additional, Le Van, B Long, additional, Loosen, P, additional, Nesladek, M, additional, Reiter, M, additional, Stahl, A, additional, Steinlechner, J, additional, Steinlechner, S, additional, Tavernier, F, additional, Teloi, M, additional, Vilaboa Pérez, J, additional, and Zeoli, M, additional

Published
2023
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7. Asgard/NOTT: L-band nulling interferometry at the VLTI. I. Simulating the expected high-contrast performance

Author

Laugier, R, primary, Defrère, D., additional, Woillez, J., additional, Courtney-Barrer, B., additional, Dannert, F., additional, Matter, A., additional, Dandumont, C., additional, Gross, S., additional, Absil, O., additional, Bigioli, A., additional, Garreau, G., additional, Labadie, L., additional, Loicq, J., additional, Martinod, M.-A., additional, Mazzoli, A., additional, Raskin, G., additional, and Sanny, A., additional

Published
2023
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8. Large Interferometer For Exoplanets (LIFE):I. Improved exoplanet detection yield estimates for a large mid-infrared space-interferometer mission

Author

Quanz, S. P., Ottiger, M., Fontanet, E., Kammerer, J., Menti, F., Dannert, F., Gheorghe, A., Absil, O., Airapetian, V. S., Alei, E., Allart, R., Angerhausen, D., Blumenthal, S., Buchhave, L. A., Cabrera, J., Carrión-González, Ó., Chauvin, G., Danchi, W. C., Dandumont, C., Defrére, D., Dorn, C., Ehrenreich, D., Ertel, S., Fridlund, M., García Muñoz, A., Gascón, C., Girard, J. H., Glauser, A., Grenfell, J. L., Guidi, G., Hagelberg, J., Helled, R., Ireland, M. J., Janson, M., Kopparapu, R. K., Korth, J., Kozakis, T., Kraus, S., Léger, A., Leedjärv, L., Lichtenberg, T., Lillo-Box, J., Linz, H., Liseau, R., Loicq, J., Mahendra, V., Malbet, F., Mathew, J., Mennesson, B., Meyer, M. R., Mishra, L., Molaverdikhani, K., Noack, L., Oza, A. V., Pallé, E., Parviainen, H., Quirrenbach, A., Rauer, H., Ribas, I., Rice, M., Romagnolo, A., Rugheimer, S., Schwieterman, E. W., Serabyn, E., Sharma, S., Stassun, K. G., Szulágyi, J., Wang, H. S., Wunderlich, F., Wyatt, M. C., Collaboration, the LIFE, Quanz, S. P., Ottiger, M., Fontanet, E., Kammerer, J., Menti, F., Dannert, F., Gheorghe, A., Absil, O., Airapetian, V. S., Alei, E., Allart, R., Angerhausen, D., Blumenthal, S., Buchhave, L. A., Cabrera, J., Carrión-González, Ó., Chauvin, G., Danchi, W. C., Dandumont, C., Defrére, D., Dorn, C., Ehrenreich, D., Ertel, S., Fridlund, M., García Muñoz, A., Gascón, C., Girard, J. H., Glauser, A., Grenfell, J. L., Guidi, G., Hagelberg, J., Helled, R., Ireland, M. J., Janson, M., Kopparapu, R. K., Korth, J., Kozakis, T., Kraus, S., Léger, A., Leedjärv, L., Lichtenberg, T., Lillo-Box, J., Linz, H., Liseau, R., Loicq, J., Mahendra, V., Malbet, F., Mathew, J., Mennesson, B., Meyer, M. R., Mishra, L., Molaverdikhani, K., Noack, L., Oza, A. V., Pallé, E., Parviainen, H., Quirrenbach, A., Rauer, H., Ribas, I., Rice, M., Romagnolo, A., Rugheimer, S., Schwieterman, E. W., Serabyn, E., Sharma, S., Stassun, K. G., Szulágyi, J., Wang, H. S., Wunderlich, F., Wyatt, M. C., and Collaboration, the LIFE

Published
2022

11. Atmospheric characterization of terrestrial exoplanets in the mid-infrared: biosignatures, habitability & diversity

Author

Quanz, S.P., Absil, O., Angerhausen, D., Benz, W., Bonfils, X., Berger, J.-P., Brogi, M., Cabrera, J., Danchi, W.C., Defrère, D., Dishoeck, E.F. van, Ehrenreich, D., Ertel, S., Fortney, J., Gaudi, S., Girard, J., Glauser, A., Grenfell, J.L., Ireland, M., Janson, M., Kammerer, J., Kitzmann, D., Kraus, S., Krause, O., Labadie, L., Lacour, S., Lichtenberg, T., Line, M., Linz, H., Loicq, J., Mennesson, B., Meyer, M.R., Miguel, Y., Monnier, J., N'Diaye, M., Pallé, E., Queloz, D., Rauer, H., Ribas, I., Rugheimer, S., Selsis, F., Serabyn, G., Snellen, I.A.G., Sozzetti, A., Stapelfeldt, K.R., Triaud, A., Udry, S., and Wyatt, M.

Abstract

Exoplanet science is one of the most thriving fields of modern astrophysics. A major goal is the atmospheric characterization of dozens of small, terrestrial exoplanets in order to search for signatures in their atmospheres that indicate biological activity, assess their ability to provide conditions for life as we know it, and investigate their expected atmospheric diversity. None of the currently adopted projects or missions, from ground or in space, can address these goals. In this White Paper we argue that a large space-based mission designed to detect and investigate thermal emission spectra of terrestrial exoplanets in the MIR wavelength range provides unique scientific potential to address these goals and surpasses the capabilities of other approaches. While NASA might be focusing on large missions that aim to detect terrestrial planets in reflected light, ESA has the opportunity to take leadership and spearhead the development of a large MIR exoplanet mission within the scope of the "Voyage 2050" long-term plan establishing Europe at the forefront of exoplanet science for decades to come. Given the ambitious science goals of such a mission, additional international partners might be interested in participating and contributing to a roadmap that, in the long run, leads to a successful implementation. A new, dedicated development program funded by ESA to help reduce development and implementation cost and further push some of the required key technologies would be a first important step in this direction. Ultimately, a large MIR exoplanet imaging mission will be needed to help answer one of mankind's most fundamental questions: "How unique is our Earth?"

Published
2019

14. Characterizing the atmosphere of Proxima b with a space-based mid-infrared nulling interferometer

Author

Creech-Eakman, M., Tuthill, P., Merand, A., Defrere, D., Leger, A., Absil, O., Garcia Munoz, A., Grenfell, J. L., Godolt, M., Loicq, J., Kammerer, Jens, Quanz, S., Rauer, H., Schifano, L., Creech-Eakman, M., Tuthill, P., Merand, A., Defrere, D., Leger, A., Absil, O., Garcia Munoz, A., Grenfell, J. L., Godolt, M., Loicq, J., Kammerer, Jens, Quanz, S., Rauer, H., and Schifano, L.

Abstract

Proxima b is our nearest potentially rocky exoplanet and represents a formidable opportunity for exoplanet science and possibly astrobiology. With an angular separation of only 35 mas (or 0.05 AU) from its host star, Proxima b is however hardly observable with current imaging telescopes and future space-based coronagraphs. One way to separate the photons of the planet from those of its host star is to use an interferometer that can easily resolve such spatial scales. In addition, its proximity to Earth and its favorable contrast ratio compared with its host M dwarf (approximately 10-5 at 10 microns) makes it an ideal target for a space-based nulling interferometer with relatively small apertures. In this paper, we present the motivation for observing this planet in the mid-infrared (5-20 microns) and the corresponding technological challenges. Then, we describe the concept of a space-based infrared interferometer with relatively small (<1m in diameter) apertures that can measure key details of Proxima b, such as its size, temperature, climate structure, as well as the presence of important atmospheric molecules such as H2O, CO2, O3, and CH4. Finally, we illustrate the concept by showing realistic observations using synthetic spectra of Proxima b computed with coupled climate chemistry models.

Published
2018

18. Review and scientific prospects of high-contrast optical stellar interferometry

Author

Tuthill, Peter G., Mérand, Antoine, Sallum, Stephanie, Defrère, D., Absil, O., Berger, J.-P., Danchi, W. C., Dandumont, C., Eisenhauer, F., Ertel, S., Gardner, T., Glauser, A., Hinz, P., Ireland, M., Kammerer, J., Kraus, S., Labadie, L., Lacour, S., Laugier, R., Loicq, J., Martin, G., Martinache, F., Martinod, M. A., Mennesson, B., Monnier, J., Norris, B., Nowak, M., Pott, J. U., Quanz, S. P., Serabyn, E., Stone, J., Tuthill, P., and Woillez, J.

Published
2020
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21. Continuous Solar Simulator for Concentrator Photovoltaic Systems

Author

Thibert, T., Hellin, M.-L., Loicq, J., Mazy, E., Gillis, J.-M., Languy, F., Habraken, S., Lecat, J.-H., and Defise, J.-M.

Subjects
Advanced Photovoltaics: New Concepts and Ultra-high Efficiency, Terrestrial Concentrator Systems
Abstract

25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 1018-1020, A continuous solar simulator for measuring performance of concentrator photovoltaic (CPV) systems is presented. The illumination system is based on a Xenon lamp, a homogenizer rod, shaping optics and a 30cm diameter collimator. The design optimises the reproduction of the characteristics of direct solar illumination: 32’ divergence, high spatial homogeneity, sun-like spectral distribution, with a maximum intensity of 250W/m². It accommodates pass-band and attenuation filters to tune the beam output. It operates in continuous mode, allowing to investigate CPV thermal aspects as well. The present paper addresses the concept design of the solar simulator and associated performance results.

Published
2010
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25. Fresnel Rhombs as Achromatic Phase Shifters for Infrared Nulling Interferometry: First experimental results

Author

Coulter, Daniel R., Hanot, C., Mawet, D., Loicq, J., Vandormael, D., Plesseria, J. Y., Surdej, J., Habraken, S., Coulter, Daniel R., Hanot, C., Mawet, D., Loicq, J., Vandormael, D., Plesseria, J. Y., Surdej, J., and Habraken, S.

Abstract

One of the most critical units of nulling interferometers is the Achromatic Phase Shifter. The concept we propose here is based on optimized Fresnel rhombs, using the total internal reflection phenomenon, modulated or not. The total internal reflection induces a phase shift between the polarization components of the incident light. We present the principles, the current status of the prototype manufacturing and testing operations, as well as preliminary experiments on a ZnSe Fresnel rhomb in the visible that have led to a first error source assessment study. Thanks to these first experimental results using a simple polarimeter arrangement, we have identified the bulk scattering as being the main error source. Fortunately, we have experimentally verified that the scattering can be mitigated using spatial filters and does not decrease the phase shifting capabilities of the ZnSe Fresnel rhomb.

Published
2007

26. Anti-reflective sub-wavelength patterning of IR optics

Author

Driggers, Ronald G., Huckridge, David A., Vandormael, D., Habraken, S., Loicq, J., Lenaerts, C., Mawet, D., Driggers, Ronald G., Huckridge, David A., Vandormael, D., Habraken, S., Loicq, J., Lenaerts, C., and Mawet, D.

Abstract

Thermal infrared (IR) lenses require efficient anti-reflection coating. Moth-eye (or egg-box) 2D subwavelength gratings have demonstrated their ability to reach a very high transmission for a wide wavelength and angular range. The use in thermal IR is simplified by the lower resolution for lithographic technology, compared to visible waveband. However, deeper structures must be engraved and lithography must be adapted to IR materials. In order to be cost-effective, the patterning must be produced by replication techniques, such as embossing. Our laboratory is now experimenting hot embossing of moth-eye patterns in chalcogenide substrates. In this paper, theoretical analysis, micro-lithographic technology and manufacturing processes are detailed.

Published
2006

46. Design of the VLTI/Hi-5 light injection system.

Author

Garreau, G., Bigioli, A., Raskin, G., Berger, J.-P., Dandumont, C., Kenchington Goldsmith, H.-D., Gross, S., Ireland, M., Labadie, L., Laugier, R., Loicq, J., Madden, S., Martin, G., Mazzoli, A., Morren, J., Shao, H., Yan, K., and Defrère, D.

Published
2022
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