Development and testing of a holographic projection system

We describe the development and testing of a holographic projection system that is used to produce micro-optical devices. The projector uses a two-dimensional two-phase-level diffraction grating to produce multiple coherent beams and an interferometric optical system behind the grating to recombine the beams to produce interference patterns that have been recorded within a photosensitive substrate. The two different substrates that we used are a diazo imaging material and a bisbenzocyclobutene (BCB) polymeric resin for fabrication of surface relief microstructures. After the exposed photosensitive substrate is developed, the recorded interference pattern forms a micro-optical device. The analysis and testing of these micro-optical devices show promise that this technique can form patterns uniformly over a region of several centimeters in diameter on flat or curved substrates. The experimental testing results of these micro-optical devices demonstrate that this method is a simple and energy efficient system to produce microstructures compared with other methods. These devices may be used as a new generation of directional light filters or monolithic microlenslet arrays that may have applications in communications, display, and components technologies.