Three-dimensional shape measurement of micro-lens arrays using full-field swept-source optical coherence tomography

Abstract

We report three-dimensional (3D) shape measurement of refracting samples using full field swept-source optical coherence tomographic (FF-SS-OCT) system. The optical arrangement of FF-SS-OCT consists of a swept-source system containing super-luminescent diode as low coherence light source and an acousto-optic tunable filter as electronically controlled frequency tuning device, a compact Michelson interferometer and an area detector. Refracting samples, such as, cylindrical lens and micro-lens arrays were used as object. By means of sweeping the frequency of the light source, multiple interferograms were recorded and both amplitude and phase map of the interference fringe signal were then reconstructed. Experimental results of optically sectioned images (tomography) of the cylindrical lens and micro-lens arrays obtained by means of selective Fourier filtering and 3D-surface profile retrieved from the phase-map are demonstrated. The proposed system does not require any mechanical scanning. In addition, a common optical path enables this proposed technique to be highly stable.