Microlens fabrication using HEBS glass for compact high-resolution IR imaging system

Under the DARPA COMP-I (Compressive Optical MONTAGE Photography Initiative) program, the goal of this project is to significantly reduce the volume and form factor of infrared imaging systems without loss of resolution. The approach taken is to use an array of small lenses with extremely short focal lengths rather than the conventional approach of a single aperture lens system with large diameter and focal length. The array of lenses creates multiple copies of the scene on a single focal plane detector array, which are then used to reconstruct an image with resolution comparable to or higher than that of the conventional imaging system. This is achieved by a computational method known as super-resolution reconstruction. Work at the University of Delaware towards this end includes participation in the design and optimization of the optical system along with fabrication of some of the optical elements. Grayscale lithography using a high-energy beam sensitive (HEBS) glass photomask and proportional dry etch pattern transfer are the key techniques enabling the fabrication process. In this paper we will discuss the design of the imaging system while focusing on the fabrication aspects of the project.