Centre National De La Recherche Scientifique

Observatoire De Paris

Thales and Centre National D'etudes Spatiales

Thales

Centre National Detudes Spatiales

Noël Dimarcq

David Holleville

Mohand Ouali Acef

Stéphane Guerandel

Frédéric Du Burck

Thomas Zanon

Stéphanie Perrin

François-Xavier Esnault

According to a first aspect, the invention relates to a generator of at least three coherent laser beams at least one beam of which is in the infrared domain and at least one beam of which is in the visible domain, comprising: an elementary source for emitting a first continuous-wave laser beam, at a first given infrared wavelength; a nonlinear crystal frequency doubler, allowing, from a first beam sampled from the first laser beam at the first wavelength, a second laser beam to be generated at a second wavelength; and a nonlinear crystal sum frequency generator, allowing, from a second beam sampled from the first laser beam at the first wavelength and from the second laser beam at the second wavelength, a third laser beam to be generated at a third wavelength.

Generator of at least three coherent laser beams in the infrared and visible domain

The invention relates to a laser source with an external cavity generating a useful laser beam (Fu), that comprises at least one laser diode DL () mounted in an extended optical cavity () defined between two reflecting surfaces () forming an optical path for a laser beam Fd generated by the laser diode DL, a mode selection filter () in the optical path of the cavity for selecting a resonance mode from a range of resonance modes of the laser beam in the cavity. The extended cavity () includes in the optical path thereof an optical device () including a polariser () that is 100% permissive to a rectilinear polarisation of the beam Fd generated by the laser diode, the reference polarisation angle &#x3b8;being of 0 degrees, a polarisation rotator () of the beam at the output of the polariser (Fc) by a predetermined rotation angle &#x3b8;, a polarisation separator () of the beam (Frt) at the output of the polarisation rotator, the polarisation separator being inclined in the cavity so that its transmission axis (tt') is oriented at an angle (&#x2212;&#x3b8;) having an opposite sign to and the same value as the polarisation angle of the beam (Frt) at the output of the rotator (), wherein the optical device prevents any feedback of a reflection beam (Fretum) of the useful beam (Fu) towards said laser diode DL. The invention can be used in a laser for cooling atoms, in interferometry experiments, inertial sensors and atomic clocks.

Compact laser source with reduced spectral width

Method for modulating an atomic clock signal and a corresponding atomic clock. The laser beams (L, L) are pulse-modulated in amplitude to illuminate (A) an interactive medium. A detection (B) of the current pulse (Sr) and of the pulses (Sr&#x2212;1 to Sr&#x2212;p) preceding said current impulsion is performed. The pulses are superimposed (C) by linear combination to generate a compensated atomic clock signal (SHC) whereof the spectral width is minimized. The invention is applicable to atomic clocks with pulsed interrogation whereof the interactive medium consists of thermal or laser-cooled atoms.

Method for modulating an atomic clock signal with coherent population trapping and corresponding atomic clock

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Etampes, France

Noël Dimarcq