Mach–Zehnder-type white light interferometer through tunable-path-difference source

Abstract

A novel scheme of white light interferometer (WLI) surface imaging system is demonstrated using a tunable-path-difference source (TPDS). TPDS is applied by adopting Mach–Zehnder interferometry to resolve the vibration noise, which the mechanical scanning has caused in the reference path of conventional WLI. Compared with WLI using comb-spacing-swept source (CSWS), WLI with TPDS is superior in terms of signal-to-noise ratio and total exposure of optical intensity into the camera. Through the improved performance, WLI with TPDS can successfully acquire 3D images at the micron scale and multi-layered tomographic information with fine detail.