Office National D'etudes Et De Recherches Aerospatiales (onera)

Office National D'etudes Et De Recherches Aerospatiales

Onera

Michel Lefebvre

Antoine Godard

Emmanuel Rosencher

Ajmal Mohamed

Myriam Raybaut

Bertrand Hardy

Aude Desormeaux

Bruno Scherrer

Nested-cavity optical parametric oscillator for fast frequency tuning including a source of pump radiation (f), a non linear crystal situated within two resonant cavities for the signal and complementary radiations of respective optical lengths land l. A doubly resonant resonator for a single pair of longitudinal signal and complementary modes is formed having a crystal of prismatic shape, the crystal () being moveable within the plane xz along a direction forming a non zero angle &#x3b2; with respect to the direction x. The value of &#x3b2; is fixed so that the movement of the crystal is accompanied by a change in the respective optical lengths land lof the two resonant cavities in a ratio such that the double resonance condition between the longitudinal modes of each cavity is maintained.

Nested-cavity optical parametric oscillator for fast frequency tuning

The invention applies to doubly resonant optical parametric oscillators comprising a non-linear crystal () through which pass a pump laser beam (f), a signal beam (f), and a complementary beam (f), and a device () that totally or partially reflects said beams emanating from the crystal such that, after reflection, they generate between them a relative phase-shifting value &#x394;&#x3a6;for a given functioning mode independent of the signal frequency or complementary frequency, and is characterized in that the reflecting device () is a metallic minor, or a combination of two scattering mirrors and a multilayer dielectric mirror placed downstream.

Optical parametric oscillator with achromatic phase-maintaining pump return

The oscillator comprises two resonant cavities in which a non-linear crystal () is situated. The incident pumping radiation Rfollows an emitting path across the crystal, the generated signal and complementary radiation carry out numerous emitted and return paths in the cavities, hence across the crystal and are thus converted into an inverse pumping radiation on the return paths thereof. According to the invention, a device () is incorporated in the oscillator for reflection of a fraction of the pumping radiation equivalent to the inverse pumping radiation in the absence of the device.

Doubly-resonant optical parametric oscillator with corresponding pump recycling

A pulsed optical parametric oscillator comprising a spectrally pure source or emitting pumping wave pulses, a non-linear crystal to which the pumping wave is applied, a resonant cavity for the complementary wave defined by two same-axis mirrors situated on opposite sides of the crystal, a cavity for the signal wave defined by two same-axis mirrors situated on opposite sides of the crystal, and means for adjusting the length of one or both cavities, wherein the oscillator is a monomode pulsed parametric oscillator and wherein one of the two mirrors for each cavity is situated between the two mirrors of the other cavity.

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Orsay, France

Michel Lefebvre