Channelled light spectrum analysis measurement method and device, more especially for measuring a low amplitude movement of a mobile surface, which may be representative of a variation of a physical magnitude convertible into such a movement

摘要

A measuring method and device are provided based on the analysis of a channelled light spectrum, particularly for measuring a low amplitude movement of a mobile surface, possibly representative of the variation of a physical magnitude convertible into such a movement. Said device comprises a two beam interferometer (3) with two reflecting surfaces, one (5) fixed and the other (6) mobile, defining a difference of the rate of progress (e) of the light rays in the interferometer, a light source (1) and an analyzer (8) for analyzing the channelled spectrum generated by said light source in said interferometer, the analyzer is formed by means (9) for spactially spreading the channelled spectrum, by means of a filter (12) whose transmission and/or reflection coefficient is periodic, at least in one direction, of fixed period equal or substantially equal, except possibly for a factor, to the period of the spatial distribution of the spatially spread spectrum; and at least one photodetector (14,14') receiving the light transmitted and/or reflected by said network for determining said difference of rate of progress.