Open AccessAcousto-optical method for measuring the displacements of a laser beam in two directions orthogonal to its axis
Author(s) -
Е. V. Leun
Publication year - 2021
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1791/1/012103
Subject(s) - optics , optical axis , physics , beam (structure) , laser , spatial light modulator , interference (communication) , laser beam quality , cylindrical lens , diffraction , phase (matter) , lens (geology) , laser beams , telecommunications , channel (broadcasting) , computer science , quantum mechanics
The issues of improving the method for controlling the two-coordinate displacements Δl y and Δl z of a laser beam in the OY and OZ directions orthogonal to its OX axis are considered. It is proposed to use a fiber photodetector with a micro-optical lens at the input of the light guide to register the interference picture produced in the Fresnel zone by the first and zero diffraction orders formed by an acousto-optical (AO) modulator. In the method, it is proposed to use a prismatic optical scheme placed in front of a single-axis AO modulator for a laser beam displaced Δl y and Δl z along two axes OY and OZ, forming two output beams. For the first beam, displacements along the OY axis are excluded: Δl y -var, Δl z =0, and the second beam is rotated relative to the first beam by 90° around the OX axis (i.e., Δl y →Δl z ) with the same exception of displacements along the OY axis with the achievement of the following: Δl y =0, Δl z -var. This technique allows you to use a single-axis (1D) AO modulator to control the two-coordinate (2D) displacements Δl y , Δl z of the initial laser beam. We also discuss the implementation of a differential measurement method by using two phase measuring devices: an interpolator and a phase meter, and the effect of signal noise on the resolution.