Multiple splitting of laser beam using surface-relief holographic diffraction element

Abstract

Grating diffraction has become a useful principle for multiple beam splitting, namely for applications in optical interconnection technology in particular 1. Grating structures of this kind can be generated by computing methods or by holographic recording. The first approach has been discussed many times after the pioneer papers of Dammann 2, and gratings for an arbitrary number of beams with equalized intensity have been obtained in practice. However, the quality depends on the ability to record as fine as possible details. Moreover, manufacturing of the primary grating is very time consuming, and requires a very complicated equipment. On the other hand, successful obtaining of the holographically recorded gratings for multiple splitting depends on the sufficiently accurate control of the grating profile because the distribution of the light flux among the diffraction orders is determined by the groove shape 3. The purpose of this paper is to show that the holographic diffraction element for multiple beam splitting of the laser beam arises in a photoresist layer exposed to the recording interference field if the layer is developed for a sufficiently long time.