Device for forming an interference grating on a sample

摘要

A device for forming an interference grating on a sample. The device including a laser emitting a light beam of wavelength λ, a beam splitter plate splitting the light beam into first and second beams, the first beam being deflected in a first direction, a first stationary deflection mirror for deflecting the first beam onto a point P of the sample at a first constant angle of incidence θ1, and at least one second stationary deflection mirror for deflecting the second beam along a final path that reaches point P of the sample at a second angle of incidence θ2 in order to form an interference grating on the sample at a pitch that depends on the angular difference θ. The device includes a movable deflection mirror to deflect the second beam from a plurality of first deflection points towards a plurality of second deflection points on the second mirror.

主权项

1. A device for forming an interference grating on a sample, the device comprising:
a laser emitting a light beam of wavelength λ, a beam splitter plate splitting the beam emitted by the laser into a first portion of a first beam and a first portion of a second beam, the first portion of the first beam being deflected in a first direction, a first stationary deflection mirror for deflecting the first portion of the first beam onto a point P of the sample at a first constant angle of incidence θ1, and and at least one second stationary deflection mirror for deflecting the first portion of the second beam along a final path that reaches said point P of the sample at a second angle of incidence θ2 in order to form an interference grating on the sample at a pitch that depends on the angular difference θ between the first angle of incidence θ1 and the second angle of incidence θ2, wherein the path of the second beam includes a deflection mirror movable in translation to direct and deflect the second beam from a plurality of first deflection points, formed by a plurality of positions of the movable mirror towards a plurality of second deflection points, formed by the positions of a plurality of second fixed mirrors having different orientations to ensure that the point P of the sample is always reached by the second beam, on a second mirror, thereby forming a plurality of pairs, each comprising first and second reflection points, each of which corresponding to a said final path of the second beam having a different value of the angle θ2, so as to cause the value of the angle of incidence θ2 to vary and thus vary the angular difference θ, and in that the first reflection points are arranged on a linear path extending from an upstream end remote from the sample where it is spaced apart from the beam emitted by the laser in the direction opposite to the first portion of the first beam to a downstream end closest to the sample, said linear path moving from the upstream end to the downstream end towards said second portion of the first beam so as to compensate at least in part for optical path length variations of the second beam for the pairs of first and second reflection points, each of which corresponds to a respective value of the angular difference θ.