Apparatus and methods for reducing non-cyclic non-linear errors in interferometry
First Claim
1. An interferometry system, comprising:
- an interferometer configured to direct a first beam and a second beam derived from common light source along different paths and to combine the two beams to form an output beam having a phase related to an optical path difference between the different paths, wherein the path of the first beam contacts a measurement object; and
an assembly positioned in the path of the first beam and configured to reduce a shear of the first beam caused by a variation in the orientation of the measurement object relative to the interferometer as it propagates within the interferometer after contacting the measurement object.
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Abstract
In general, in one aspect, the invention features interferometry systems that include an interferometer configured to direct a first beam and a second beam derived from common light source along different paths and to combine the two beams to form an output beam including information related to an optical path difference between the different paths, wherein the path of the first beam contacts a measurement object. The interferometry systems also include an afocal system positioned in the path of the first beam and configured to increase a dimension of the first beam as it propagates from the interferometer towards the measurement object and reduces the dimension of the first beam as it returns from the measurement object propagating towards the interferometer.
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Citations
32 Claims
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1. An interferometry system, comprising:
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an interferometer configured to direct a first beam and a second beam derived from common light source along different paths and to combine the two beams to form an output beam having a phase related to an optical path difference between the different paths, wherein the path of the first beam contacts a measurement object; and
an assembly positioned in the path of the first beam and configured to reduce a shear of the first beam caused by a variation in the orientation of the measurement object relative to the interferometer as it propagates within the interferometer after contacting the measurement object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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12. An interferometry system, comprising:
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an interferometer configured to direct a first beam and a second beam derived from common light source along different paths and to combine the two beams to form an output beam having a phase related to an optical path difference between the different paths, wherein the path of the first beam contacts a measurement object; and
an afocal system positioned in the path of the first beam between the interferometer and the measurement object and configured to change a diameter of the first beam relative to the first beam'"'"'s diameter as it exits the interferometer propagating towards the measurement object.
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25. An interferometry system, comprising:
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an interferometer configured to direct a first beam and a second beam derived from common light source along different paths and to combine the two beams to form an output beam including information related to an optical path difference between the different paths, wherein the path of the first beam contacts a measurement object; and
an afocal system positioned in the path of the first beam and configured to increase a dimension of the first beam as it propagates from the interferometer towards the measurement object and reduces the dimension of the first beam as it returns from the measurement object propagating towards the interferometer. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32)
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Specification