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A portable, rugged, inexpensive shearing interferometer is described and evaluated. Originally intended for application to plasma and flow analysis, it is also a suitable instructional aid. The shearing is obtained by the offset of the reflection from the first surface of a mirror relative to the reflection from the second surface when the mirror is set at an angle to the illuminating beam. The sensitivity is equivalent to that of a schlieren system. However, no schlieren quality components are involved and there are no critical adjustments or dimensions.
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Kelley et al. (1970) studied this question.
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