Abstract

The homogeneity test of glass plates in a Fizeau interferometer requires the measurement of the glass sample in reflected as well as in transmitted light. For the measurement in transmitted light, the sample has to be inserted into the ray path of a Fizeau or Twyman–Green interferometer, which leads to a nested cavity setup. To separate the interference signals from the different cavities, we illuminate a Fizeau interferometer with an adaptive frequency comb. In this way, rigid glass plates can be measured, and linear variations in the homogeneity can also be detected. The adaptive frequency comb is provided by a variable Fabry–Perot filter under broadband illumination from a superluminescence diode. Compared to approaches using a two-beam interferometer as a filter for the broadband light source, the visibility of the fringe system is considerably higher.

© 2013 Optical Society of America

Adaptive frequency comb illumination for interferometry in the case of nested two-beam cavities

Irina Harder, Gerd Leuchs, Klaus Mantel, and Johannes Schwider
Appl. Opt. 50(25) 4942-4956 (2011)

Superposition fringes as a measuring tool in optical testing

J. Schwider
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Homogeneity testing of optical glass by holographic interferometry

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Modified Roberts-Langenbeck test for measuring thickness and refractive index variation of silicon wafers

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White-light Fizeau interferometer

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