Digital mirror devices and liquid crystal displays in maskless lithography for fabrication of polymer-based holographic structures

Abstract

Polymer-based holographic and diffractive optical elements have gained increasing interest due to their potential to be used in a broad range of applications, such as illumination technology, micro-optics, and holography. We present a production process to fabricate polymer-based diffractive optical elements and holograms. The process is based on maskless lithography, which is used to fabricate optical elements in photoresist. We discuss several lab-level lithography setups based on digital mirror devices and liquid crystal devices with respect to illumination efficiency, resolution, and contrast. The entire optical setup is designed with emphasis on low-cost components, which can be easily implemented in an optical research lab. In a first step, a copy of the microstructures is replicated into optical polymeric materials by means of a soft stamp hot embossing process. The soft stamp is made from polydimethylsiloxan, which is coated onto the microstructure in the photoresist. The hot embossing process is carried out by a self-made and low-cost hot embossing machine. We present confocal topography measurements to quantify the replication accuracy of the process and demonstrate diffractive optical elements and holographic structures, which were fabricated using the process presented. © 2015 Society of Photo-Optical Instrumentation Engineers (SPIE).