Spatial coherence in interferometry: Zygo's new method to reduce intrinsic noise in interferometers

Abstract

This paper describes a new light source, called the "Ring of Fire™" (RoF), with a specific spatial coherence function, which greatly reduces the intrinsic instrument noise. The evaluation of a series of very simple measurements taken with a conventional point light source and the RoF show clearly the very large gain in S/N ratio as a function of spatial frequencies obtained with this new light source.