<title>Some studies on application of binary optical elements</title>

Abstract

Binary optical elements have been developed well over the past few years. This article gives the results of studies on the application of binary optical elements in four-channel two-frequency interferometer. To correct mechanical errors of measurement in real-time, a beam-splitter is needed to split laser beams to measure different parameters. In this interferometer, binary optical elements are employed as a beam-splitter and deflector instead of prisms. The volume and weight of the interferometer are reduced a lot by using them. These elements are easy to regulate and work well. The piece of glass is a 2D Dammanm grating, which split the original beam into four beams with equal intensity. Another glass plate with four gratings is used as deflector to make these beams to run parallel to each other. The parallelism of split beams is less than 15 arc seconds. In the experiment, no observable phenomenon of depolarization was found. It means that binary optical elements can be employed in two-frequency interferometer. The main disadvantage of binary optical elements is its low diffraction efficiency. When the beam pass through binary optical elements, about eighty percent of its amplitude is lost.