For 4D Technology, some of the biggest recent developments in optical metrology equipment come in a Fizeau interferometer --an interferometric arrangement that places two reflecting surfaces facing each other.
Since the early days of laser interferometry, optical manufacturers have depended on Fizeau interferometers as the workhorse of the polishing shop.'
4 small fragments of the sphere are measured with the use of Fizeau interferometer and then the procedure of stitching is applied to obtain the image of the whole surface.
This system applies a modified Fizeau interferometer, too.
Key words: angle; autocollimator; Fizeau interferometer
; metrology; phase shifting.
Optical Surfaces has developed a 600mm Fizeau interferometer
enabling it to now offer quality testing of flats in a single aperture up to 600mm in diameter.