319 Fabrication of fresnel lens for ultra wide field-of-view optics for cosmic ray detection

Abstract

The new fabrication system of double-sided fresnel lenses with 400mm aperture is proposed in this paper. A large ultraprecision machine tool, a rotary table with air-hydrostatic bearing and a laser displacement probe for an on-machine measurement were developed for this purpose. The authors applied a micro-turning technique using diamond tools to fabricate the elements, and successfully obtained the required element with a sharp and smooth V-faced fresnel structure in both sides using spherical substrates of acrylic.