Phase shifting interferometry with multiple accumulation
AssigneeZygo Corporation
InventorsPeter De Groot, Leslie L. Deck
Life of this patent
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Abstract
An interferometer system is disclosed which is configured to combine measurement light with reference light to form an optical interference pattern, where the interferometer system includes a modulator configured to repetitively introduce a sequence of phase shifts between the measurement and reference light; and a camera system positioned to measure the optical interference pattern, where the camera system is configured to separately accumulate time-integrated images of the optical interference pattern corresponding to the different phase shifts in the sequence during the repetitions of the sequence.
Claims35
An apparatus comprising:
- an interferometer system configured to combine measurement light with reference light to form an optical interference pattern, the interferometer system comprising a modulator configured to repetitively introduce a sequence of different phase shifts between the measurement and reference light;
- and
- a camera system positioned to measure the optical interference pattern, wherein the camera system is configured to separately accumulate time-integrated images of the optical interference pattern corresponding to the different phase shifts in the sequence during the repetitions of the sequences
- wherein each of the separately accumulated time-integrated images is integrated for a different one of the different phase shifts over multiple repetitions of the sequence.
An apparatus comprising:
- an interferometer system configured to combine measurement light with reference light to form an optical interference pattern, the interferometer system comprising a modulator means for repetitively introducing a sequence of different phase shifts between the measurement and reference light;
- and
- a camera means for separately accumulating time-integrated images of the optical interference pattern corresponding to the different phase shifts in the sequence during the repetitions of the sequence,
- wherein each of the separately accumulated time-integrated images is integrated for a different one of the different phase shifts over multiple repetitions of the sequence.
A method comprising:
- combining measurement light with reference light to form an optical interference pattern;
- repetitively introducing a sequence of different phase shifts between the measurement and reference light;
- and
- separately accumulating time-integrated images of the optical interference pattern in a camera system, wherein the time-integrated images correspond to the different phase shifts in the sequence during the repetitions of the sequence and each of the separately accumulated time-integrated images is integrated for a different one of the different phase shifts over multiple repetitions of the sequence.
An apparatus comprising:
- an interferometer system configured to combine measurement light with reference light to form an optical interference pattern, the interferometer system comprising a modulator configured to repetitively introduce a sequence of phase shifts between the measurement and reference light;
- and
- a camera system positioned to measure the optical interference pattern, wherein the camera system is configured to separately accumulate time-integrated images of the optical interference pattern corresponding to the different phase shifts in the sequence during the repetitions of the sequence,
- wherein the camera system comprises a camera having multiple sets of elements, wherein each set of elements comprise a light-sensitive pixel and multiple storage cells coupled to the light-sensitive pixels to store electrical information from the light sensitive pixel in accordance with the sequence of phase shifts.
Dependencies are inferred from the claim text.