This paper describes theory and performance of a self- developed IR phase-shifting digital interferometer which uses a CO₂ laser as light source, this instrument comprises of a Fizeau interferometer whose aperture reaches (Phi) 250mm with accuracy better than (lambda) /50, and a Twyman spherical interferometer. Using piezoelectric transducer to shift reference mirror, phase measurement interferometry can be carried out as well as the temperature modulation of PEV target. A series of software packages used as wavefront fitting, image quality evaluation, are incorporated into the instrument. With the help of microcomputer, this interferometric system can measure refractive-index homogeneity of IR transmitting materials, wavefront error of IR optical system and surface quality of rough surface etc., which can all be shown by detailed data of optical path difference, vivid 2D contour and 3D surface.

Date Published: 3 October 1996
PDF: 7 pages
Proc. SPIE 2899, Automated Optical Inspection for Industry, (3 October 1996); doi: 10.1117/12.253083

Published in SPIE Proceedings Vol. 2899:
Automated Optical Inspection for Industry
Frederick Y. Wu; Shenghua Ye, Editor(s)