Interference measurement of continuous heterogeneities in optical materials.
A measuring method is described which is not limited by interferometer errors. Variations in the geometrical and optical thickness of the block under investigation and its refractive index may be measured by means of scanning three interferograms and using computer analysis. There also exists a possibility of calculating the rate of variation of these quantities according to coordinate alteration of the investigated block. Some measurement results are given, and analysis of measuring accuracy is carried out. Measuring accuracy for refractive index difference distribution may reach one part in 1 x 10(-7) for centimeter thick samples.
Kowalik
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