High quality diffractive optical elements (DOEs) using SMILE imprint technique

Abstract

Augmented reality (AR) enhancing the existing natural environment by overlaying a virtual world is an emerging and growing market and attracts huge commercial interest into optical devices which can be implemented into head-mounted AR equipment. Diffractive optical elements (DOEs) are considered as the most promising candidate to meet the market's requirements such as compactness, low-cost, and reliability. Hence, they allow building alternatives to large display headsets for virtual reality (VR) by lightweight glasses. Soft lithography replication offers a pathway to the fabrication of large area DOEs with high aspect ratios, multilevel features, and critical dimensions below the diffractive optical limit down to 50 nm also in the scope of mass manufacturing. In combination with tailored UV-curable photopolymers, the fabrication time can be drastically reduced making it very appealing to industrial applications. Here, we illustrate the key features of high efficiency DOEs and how the SMILE (SUSS MicroTec Imprint Lithography Equipment) technique can be used with advanced imprint photopolymers to obtain high quality binary DOEs meeting the market's requirements providing a very versatile tool to imprint both nano- and microstructures.