Fringe scanning shearing interferometer
First Claim
1. A fringe scanning shearing interferometer comprising:
- (a) converter means for converting a wavefront reflected by an object under test, illuminated with light, into an approximately parallel wavefront;
(b) splitter means for dividing said approximately parallel wavefront into first and second wavefronts travelling in two directions;
(c) a pair of first and second optical path changing means which conduct the first and second wavefronts, respectively, and are disposed respectively adjacent to said splitter means in equally spaced relation thereto;
(d) displacement means for displacing said first optical path changing means in a direction normal to the direction in which said first wavefront falls on said first optical path changing means;
(e) shearing means for slightly displacing said second optical path changing means in the same direction as that in which second wavefront falls on said second optical path changing means;
(f) a photodetector; and
(g) a focusing lens for focusing said first and second wavefronts, which have passed respectively through said first and second optical path changing means and have been directed thereby so that they can be focused by said focusing lens, on said photodetector to produce interference fringes thereon.
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Abstract
A fringe scanning shearing interferometer includes a converter lens for converting a wavefront reflected by an object under test illuminated with light into an approximately parallel wavefront, a beam splitter for dividing the approximately parallel wavefront into first and second wavefronts travelling in two directions, a pair of first and second prisms disposed respectively adjacent to the beam splitter in equally spaced relation thereto, a displacement mechanism for displacing the first prism in a direction normal to the direction in which the first wavefront falls on the first prism, a shearing device for slightly displacing the second prism in the same direction as that in which the second wavefront falls on the second prism, a photodetector, and a focusing lens for focusing the first and second wavefronts having passed respectively through the first and second prism, on the photodetector to produce interference fringes thereon.
15 Citations
18 Claims
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1. A fringe scanning shearing interferometer comprising:
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(a) converter means for converting a wavefront reflected by an object under test, illuminated with light, into an approximately parallel wavefront; (b) splitter means for dividing said approximately parallel wavefront into first and second wavefronts travelling in two directions; (c) a pair of first and second optical path changing means which conduct the first and second wavefronts, respectively, and are disposed respectively adjacent to said splitter means in equally spaced relation thereto; (d) displacement means for displacing said first optical path changing means in a direction normal to the direction in which said first wavefront falls on said first optical path changing means; (e) shearing means for slightly displacing said second optical path changing means in the same direction as that in which second wavefront falls on said second optical path changing means; (f) a photodetector; and (g) a focusing lens for focusing said first and second wavefronts, which have passed respectively through said first and second optical path changing means and have been directed thereby so that they can be focused by said focusing lens, on said photodetector to produce interference fringes thereon. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification