Nouvelle approche dans la mesure de la largeur d'une fente

Abstract

A method to measure the width of a slit which is based on the phenomenon of fringes of equal chromatic order is described. The use of spectral fringes for this application is new and differs totally from the method normally used in industrial metrology laboratories. In the latter case, one uses a high quality instrument to measure with precision the distance a slit has to move in order for the operator to bring a carefully adjusted microscopic reticle from coincidence with one edge of the slit to coincidence with the other. In the proposed method, we measure the alternating component of the luminous flux through the slit when a cosinusoidaly modulated light distribution is moved in front of the slit. A null alternating component indicates equality between the width of the slit and the spacing of the fringes. This approach, although requiring more complex instrumentation, introduces a new dimension in industrial metrology related to the measure of the width of a slit.[Journal translation]