
206 OPTICS FOR ENGINEERS
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Figure 7.14 Michelson interferometer. Light from the source is split into two paths by the
beamsplitter. One path is reflected from each mirror, and the two are recombined at the same
beamsplitter.
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Transit time
Geometric optics
Figure 7.15 Straight-line layout. The path lengths can be determined from the distances and
indices of refraction. Light on one path passes through the substrate of the beamsplitter once, but
light on the other path does so three times. Increased index of refraction lengthens the optical
path, but shortens the geometric path.
the beamsplitter. One path serves as a reference ...