US 12,305,981 B2
Low-coherence interferometer with surface power compensation
Joshua Monroe Cobb, Victor, NY (US); and Steven James Van Kerkhove, Webster, NY (US)
Assigned to CORNING INCORPORATED, Corning, NY (US)
Filed by CORNING INCORPORATED, Corning, NY (US)
Filed on Nov. 7, 2022, as Appl. No. 17/981,674.
Claims priority of provisional application 63/282,946, filed on Nov. 24, 2021.
Prior Publication US 2023/0160686 A1, May 25, 2023
Int. Cl. G01B 9/0209 (2022.01); G01B 9/02 (2022.01); G01B 11/24 (2006.01); G01B 11/30 (2006.01); G02B 27/10 (2006.01)
CPC G01B 9/0209 (2013.01) [G01B 9/02041 (2013.01); G01B 11/2441 (2013.01); G01B 11/30 (2013.01); G02B 27/1006 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A low-coherence Fizeau interferometer comprising:
a low-coherence light source optically coupled to a first beamsplitter;
a test arm and a reference arm optically coupled to the first beamsplitter, the first beamsplitter configured to receive light emitted from the low-coherence light source and split the received light into a first portion of light directed to the test arm and a second portion of light directed to the reference arm; and
an imaging arm comprising a second collimating lens, a flat reference surface, and a test element, the imaging arm optically coupled to the first beamsplitter through a second beam splitter, wherein:
the test arm comprises a selectively movable optical element configured to focus the first portion of light at a first focal point and adjust a position of the first focal point, along an optical propagation path between the first beamsplitter and the second beamsplitter optically coupling the first beamsplitter to the imaging arm,
the reference arm is configured to focus the second portion of light at a second focal point along the optical propagation path so that the second portion of light directed by the second beam splitter is collimated by the second collimating lens and reflects off the flat reference surface,
the second beamsplitter is configured to direct the first portion of light diverging from the first focal point through the flat reference surface to reflect off the test element, and
the reflection of the first portion of light and the second portion of light interfere to form an interference pattern.