Institut National D'optique

Gentec

Pierre Langlois

Pierre Galarneau

Yves Painchaud

Jocelyn Lauzon

Alain Chandonnet

Marie Cote

Michel Belanger

Francois Trepanier

Julie Frechette

Jean-Marie Trudeau

A device and method for recording holographic gratings by the use of a single illuminating beam, two diffraction gratings, light detectors and a slit-scanning system. The beam illuminates two slits that then define two beams that are incident on the gratings. One diffracted order from one beam and one diffracted order from the other beam then interfere on a recording plane to produce sinusoidal variations of intensity. The interfering region may instantaneously be limited by a third slit. Also, another order of diffraction from one beam may be directed toward its own light detector and so is another order of diffraction from the other beam. These two detectors allow real time monitoring of the light intensity of each beam. By moving the slits in a direction parallel to the recording plane, an area larger than the slits' width can be exposed by the interfering pattern.

Device and method for recording an interference pattern in a photosensitive medium

A method for spatially controlling the period and amplitude of Bragg filters in an optical medium having a longitudinal axis that is sensitive to at least some wavelength of electromagnetic radiation. A phase mask of period .LAMBDA. is laid close to the optical medium at an angle .alpha. with respect to the longitudinal axis of the optical medium. A single beam of electromagnetic radiation is directed at an incidence angle .phi. with respect to normal incidence on the phase mask so that the radiation is diffracted, resulting in an interference pattern having a period P impinged into the optical medium so that the period P of the interference pattern may be altered by changing the incidence angle .phi. or the angle .alpha.. This method is simpler, more flexible and more suitable for mass production than existing methods.

Method for spatially controlling the period and amplitude of BRAGG

A method for spatially controlling the period and amplitude of Bragg filters in an optical medium having a longitudinal axis that is sensitive to at least some wavelength of electromagnetic radiation. A phase mask of period .LAMBDA. is laid close to the optical medium at an angle .alpha. with respect to the longitudinal axis of the optical medium. A single beam of electromagnetic radiation is directed at an incidence angle .phi. with respect to normal incidence on the phase mask so that the radiation is diffracted, resulting in an interference pattern having a period P impinged into the optical medium so that the period P of the interference pattern may be altered by changing the incidence angle .phi. or the angle .alpha. . This method is simpler, more flexible and more suitable for mass production than existing methods.

Method for spatially controlling the period and amplitude of Bragg

A beam sampler comprises a substrate made of highly transparent fused silica or zinc selenide, both capable of sustaining high power laser beams. The substrate defines an outer surface through which the light beam being sampled propagates. A sinusoidal diffracting relief is etched on this outer surface directly into the light-propagating material of the substrate. When a light beam propagates through the outer surface of the substrate, the three-dimensional diffracting relief extracts from this light beam at least one pair of low power beam samples.

High power laser beam sampler

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Ste-Catherine-de-la-Jacques-Cartier, Canada

Pierre Langlois