摘要:
A holographic process is provided for recording-reading by means of index strata in the volume of a photoexcitable storage medium. This process consists in causing two beams to interfere in this medium during two successive writing steps by using writing radiations of different wavelengths. The reading of this medium is then effected by means of a third coherent radiation having for wave vector in the medium a linear combination of the wave vectors of said writing radiations.
摘要:
The invention relates to the interferometric detection of reciprocal and non-reciprocal effects affecting the propagation of optical radiation in a two-armed interferometer. The invention relates to a two-armed interferometer terminating by a photorefractive medium used as an interactive reflector according to the four-wave interferometer principle.The invention particularly applies to the measurement of physical quantities such as displacement, linear velocity, angular velocity, magnetic field, pressure and temperature.
摘要:
An interferometric device for measuring an angular rotational speed comprising an amplifying photo refractive crystal placed in the path of optical guide means forming a closed loop. Two signal waves penetrate into said crystal so as to obtain two contrarotating waves of different optical frequencies and of amplitudes restored by amplification in the crystal, moving in said closed loop.
摘要:
The invention relates to a broadband light source including an amplifying guide structure (1). The light source includes a device (45) of exciting the guide structure (1). The stimulated guide structure (1) emits light (7, 8) that accepts strong spatial coherence and weak time coherence. The light (7) is transmitted forwards (2) having a spontaneous emission spectrum. The light source also includes a rear mirror (5), reflecting only for a narrower range of wavelengths than the spontaneous emission spectrum and produces emission (E) forwards (2) with an emission spectrum controlled around an average wavelength. The rear mirror is inserted between the excitation means and the guide structure.
摘要:
In an optical fiber sensor, the fiber has a sensitive zone which cooperates with a retroreflecting surface through the agency of an optical couplant. The function of the retroreflecting surface is to return into the optical fiber all light losses which escape from the fiber in the sensitive zone.
摘要:
The invention provides a process for forming a fiber keeping a circular polarization and a device for implementing this process.This process consists, during drawing and twisting of the fiber from a formable material source, in remelting on the surface a part of the volume of said fiber in a zone where it is subjected to twisting stresses.
摘要:
A heating device including a carbon dioxide laser beam directed towards a spherical mirror and then directed from an ellipsoidal mirror so as to concentrate the energy of said laser on a surface ring of a threadlike object.
摘要:
The invention relates to electro-optical media which make it possible to record holograms in real time. It consists in using a lamina of a selected material such as bismuth-silicon oxide, this lamina being subjected to a transverse electric field perpendicular to the fringes of the hologram to be inscribed, and in illuminating this lamina with a light beam which is not coherent with the two object and reference beams which interfere within this lamina.
摘要:
The invention relates to ring interferometers. It aims at making strictly reciprocal a ring interferometer of any known structure, by means of a mode filter which allow a particular mode to be selected among all the modes likely to be propagated in the loop and to arrive at the detection device; this filtering is carried out by a mode filter comprising for example a screen pierced with a hole or an integrated wave-guide or optical fiber portion which are advantageously monomode.
摘要:
The invention relates to a device for measuring a magnetic field, comprising a source of rectilinearly polarized light. A magnetooptical medium is situated in the path of the beam, this medium being followed by a mirror refecting this beam. This medium is a medium of which the intrinsic propagation modes are polarized in right-hand and left-hand directions, and which retains the circular polarization. An element acting as a separator by polarization is situated between the source and the medium, a detector device being coupled to the same.