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

Onera (office National D'etudes Et De Recherches Aerospatiales)

Onera

Ajmal Mohamed

Michel Lefebvre

Antoine Godard

Raphaël Vallon

An optical probe for measuring physical and chemical characteristics of a transparent fluid medium during flow comprises two fingers parallel to one another and to the flow. Each finger consists of a solid bar of transparent material, in which a light beam propagates and is reflected on an end face of the bar, said face being situated upstream in the flow. Such an optical probe may be reduced in size, and provides results which are less sensitive to disturbances of the flow that are caused by the probe itself.

Optical probe for measuring physical and chemical characteristics of a medium during flow

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.

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Palaiseau, France

Ajmal Mohamed