Prof. Patricia Segonds Profile

Prof. Patricia Segonds

at Institut NÉEL

SPIE Involvement:

Author

Publications (10)

Proceedings Article | 10 March 2020 Presentation

Direct studies on nonlinear oxide crystals able to generate mid-infrared parametric light (Conference Presentation)

Patricia Segonds, Benoit Boulanger

Proceedings Volume 11281, 112811I (2020) https://doi.org/10.1117/12.2555168

Read Abstract +

Proceedings Article | 9 March 2020 Presentation

Calculation of THz emission from phase-matched difference-frequency-generation in eight nonlinear crystals from time-domain-spectroscopy data (Conference Presentation)

Benoit Boulanger, Cyril Bernerd, Patricia Segonds, Jérôme Debray, Jean-Francois Roux, Emilie Herault, Jean-Louis Coutaz, Ichiro Shoji, Hiroaki Minamide, Hiromasa Ito, Dominique Lupinski, Kevin Zawilski, Peter Schunemann, Xinyuan Zhang, Jiyang Wang

Proceedings Volume 11264, 1126418 (2020) https://doi.org/10.1117/12.2550505

KEYWORDS: Terahertz radiation, Nonlinear crystals, Imaging spectroscopy, Crystals, Silver, Zinc oxide, Spectroscopy, Absorption, Visible radiation, Nonlinear optics

Read Abstract +

Proceedings Article | 9 March 2020 Presentation

Determination of Sellmeier’s equations and nonlinear coefficients of the BGSe crystal, and calculation of infrared emission from phase-matched optical parametric generation (Conference Presentation)

Benoit Boulanger, Feng Guo, Patricia Segonds, Elodie Boursier, Jérôme Debray, Valeriy Badikov, Dmitrii Badikov, Vladimir Panyutin, Valentin Petrov

Proceedings Volume 11264, 112640T (2020) https://doi.org/10.1117/12.2550580

KEYWORDS: Nonlinear crystals, Crystals, Second-harmonic generation, Nonlinear optics, Infrared radiation, Atmospheric optics, Phase measurement, Optical spheres, Atmospheric monitoring, Gas lasers

Read Abstract +

Proceedings Article | 28 February 2014 Paper

Composition, geometry and polarization influences on spectroscopic properties of Yb-doped LLnB (Ln= Y, Gd) monoclinic crystals

Marie Chavoutier, Hassan Ajrouche, Yannick Petit, Alain Garcia, Philippe Veber, Alexandre Fargues, Oudomsack Viraphong, Véronique Jubera, Inka Manek-Hönninger, Patricia Segonds, Jérôme Debray, Bertrand Ménaert, Vincent Rodriguez, Frédéric Adamietz

Proceedings Volume 8959, 89591M (2014) https://doi.org/10.1117/12.2039496

KEYWORDS: Crystals, Dielectrics, Absorption, Dielectric polarization, Luminescence, Laser crystals, Spectroscopy, Gadolinium, Polarization, Polishing

Read Abstract +

Proceedings Article | 24 February 2009 Paper

Angular quasi-phase-matching: theory and first experiments

Pierre Brand, Benoît Boulanger, Patricia Segonds, Yannick Petit, Corinne Félix, Bertrand Ménaert, Takunori Taira, Hideki Ishizuki

Proceedings Volume 7197, 719706 (2009) https://doi.org/10.1117/12.810138

KEYWORDS: Second-harmonic generation, Beam propagation method, Crystals, Information operations, Refractive index, Optical spheres, Polarization, Wave propagation, Birefringence, NOx

Read Abstract +

Proceedings Article | 17 November 2000 Paper

ELP-OA: measuring the wavefront tilt without a natural guide star

Matthias Schoeck, Jean-Paul Pique, Alain Petit, Patrick Chevrou, Vincent Michau, Gilbert Grynberg, Arnold Migus, Nancy Ageorges, Veronique Bellanger, Francois Biraben, Ruy Deron, Hayden Fews, Francoise-Claude Foy, Claudia Hoegemann, Markus Laubscher, Daniel Mueller, Celine d'Orgeville, Olivier Peillet, Mike Redfern, Renaud Foy, Patricia Segonds, Richard Soden, Michel Tallon, Eric Thiebaut, Andrei Tokovinin, Jerome Vaillant, Jean-Marc Weulersse

Proceedings Volume 4125, (2000) https://doi.org/10.1117/12.409304

KEYWORDS: Telescopes, Stars, Sodium, Wavefronts, Adaptive optics, Modulation, Laser guide stars, Oscillators, Astronomy, Chemical species

Read Abstract +

Proceedings Article | 16 August 2000 Paper

Polychromatic guide star: feasibility study

Renaud Foy, Jean-Paul Pique, Alain Petit, Patrick Chevrou, Vincent Michau, Gilbert Grynberg, Arnold Migus, Nancy Ageorges, Veronique Bellanger, Francois Biraben, Ruy Deron, Hayden Fews, Francoise-Claude Foy, Claudia Hoegemann, Markus Laubscher, Daniel Mueller, Celine d'Orgeville, Olivier Peillet, Mike Redfern, Matthias Schoeck, Patricia Segonds, Richard Soden, Michel Tallon, Eric Thiebaut, Andrei Tokovinin, Jerome Vaillant, Jean-Marc Weulersse

Proceedings Volume 4065, (2000) https://doi.org/10.1117/12.407359

KEYWORDS: Telescopes, Sodium, Stars, Oscillators, Adaptive optics, Modulation, Wavefronts, Chemical species, Photons, Laser guide stars

Read Abstract +

Adaptive optics at astronomical telescopes aims at correcting in real time the phase corrugations of incoming wavefronts caused by the turbulent atmosphere, as early proposed by Babcock. Measuring the phase errors requires a bright source located within the isoplanatic patch of the program source. The probability that such a reference source exists is a function of the wavelength, of the required image quality (Strehl ratio), of the turbulence optical properties, and of the direction of the observation. It turns out that the sky coverage is disastrously low in particular in the visible wavelength range where, unfortunately, the gain in spatial resolution brought by adaptive optics is the largest. Foy and Labeyrie have proposed to overcome this difficulty by creating an artificial point source in the sky in the direction of the observation relying on the backscattered light due to a laser beam. This laser guide star (hereinafter referred to as LGS) can be bright enough to allow us to accurately measure the wavefront phase errors, except for two modes which are the piston (not relevant in this case) and the tilt. Pilkington has emphasized that the round trip time of the laser beam to the mesosphere, where the LGS is most often formed, is significantly shorter than the typical tilt coherence time; then the inverse-return-of-light principle causes deflections of the outgoing and the ingoing beams to cancel. The apparent direction of the LGS is independent of the tilt. Therefore the tilt cannot be measured only from the LGS. Until now, the way to overcome this difficulty has been to use a natural guide star to sense the tilt. Although the tilt is sensed through the entire telescope pupil, one cannot use a faint source because $APEX 90% of the variance of the phase error is in the tilt. Therefore, correcting the tilt requires a higher accuracy of the measurements than for higher orders of the wavefront. Hence current adaptive optics devices coupled with a LGS face low sky coverage. Several methods have been proposed to get a partial sky coverage for the tilt. The only one providing us with a full sky coverage is the polychromatic LGS (hereafter referred to as PLGS). We present here a progress report of the R&D program Etoile Laser Polychromatique et Optique Adaptative (ELP-OA) carried out in France to develop the PLGS concept. After a short recall of the principles of the PLGS, we will review the goal of ELP-OA and the steps to get over to bring it into play. We finally shortly described the effort in Europe to develop the LGS.

Proceedings Article | 7 July 2000 Paper

PASS-2: quantitative photometric measurements of the polychromatic laser guide star

Matthias Schoeck, Renaud Foy, Jean-Paul Pique, Patrick Chevrou, Nancy Ageorges, Alain Petit, Veronique Bellanger, Hayden Fews, Francoise-Claude Foy, Claudia Hoegemann, Markus Laubscher, Olivier Peillet, Patricia Segonds, Michel Tallon, Jean-Marc Weulersse

Proceedings Volume 4007, (2000) https://doi.org/10.1117/12.390338

KEYWORDS: Laser guide stars, Telescopes, Sodium, Stars, Global system for mobile communications, Oscillators, Wavefronts, Adaptive optics, Calibration, Photometry

Read Abstract +

Proceedings Article | 7 July 2000 Paper

ELPOA: toward the tilt measurement from a polychromatic laser guide star

Proceedings Volume 4007, (2000) https://doi.org/10.1117/12.390401

KEYWORDS: Telescopes, Sodium, Oscillators, Adaptive optics, Modulation, Laser guide stars, Photons, Chemical species, Wavefronts, Atmospheric optics

Read Abstract +

Adaptive optics at astronomical telescopes aims at correcting in real time the phase corrugations of incoming wavefronts caused by the turbulent atmosphere, as early proposed by Babcock. Measuring the phase errors requires a bright source, which is located within the isoplanatic patch of the program source. The probability that such a reference source exists is a function of the wavelength of the observation, of the required image quality (Strehl ratio), of the turbulence optical properties, and of the direction of the observation. Several papers have addressed the problem of the sky coverage as a function of these parameters (see e.g.: Le Louarn et al). It turns out that the sky coverage is disastrously low in particular in the short (visible) wavelength range where, unfortunately, the gain in spatial resolution brought by adaptive optics is the largest. Foy and Labeyrie have proposed to overcome this difficulty by creating an artificial point source in the sky in the direction of the observation relying on the backscattered light due to a laser beam. This laser guide star (hereafter referred to as LGS) can be bright enough to allow us to accurately measure the wavefront phase errors, except for two modes which are the piston (which is not relevant in this case) and the tilt. Pilkington has emphasized that the round trip time of the laser beam to the mesosphere, where the LGS is most often formed, is significantly shorter than the typical tilt coherence time; then the inverse-return- of-light principle causes deflections of the outgoing and the ingoing beams to cancel. The apparent direction of the LGS is independent of the tilt. Therefore the tilt cannot be measured only from the LGS. Until now, the way to overcome this difficulty has been to use a natural guide star to sense the tilt. Although the tilt is sensed through the entire telescope pupil, one cannot use a faint source because approximately equals 90% of the variance of the phase error is in the tilt. Therefore, correcting the tilt requires a higher accuracy of the measurements than for higher orders of the wavefront. Hence current adaptive optics devices coupled with a LGS face low sky coverage. Several methods have been proposed to get a partial or total sky coverage for the tilt, such as the dual adaptive optics concept, the elongation perspective method, or the polychromatic LGS (hereafter referred to as PLGS). We present here a progress report of the R&D program Etoile Laser Polychromatique et Optique Adaptative (ELP-OA) carried out in France to develop the PLGS concept. After a short recall of the principles of the PLGS, we will review the goal of ELP-OA and the steps to get over to bring it into play.

Proceedings Article | 27 September 1999 Paper

PASS-2: photometry of the polychromatic laser guide star

Matthias Schoeck, Renaud Foy, Jean-Paul Pique, Michel Tallon, Patricia Segonds, Markus Laubscher, Olivier Peillet

Proceedings Volume 3762, (1999) https://doi.org/10.1117/12.363589

KEYWORDS: Laser guide stars, Sodium, Telescopes, Ultraviolet radiation, Pulsed laser operation, Mirrors, Wavefronts, Adaptive optics, Stars, Atmospheric corrections

Read Abstract +

Showing 5 of 10 publications

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years