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US 12,676,447 B2Granted
Apparatus for and method of optical component alignment
AssigneeCymer, Inc.
InventorsHong Ye, Eric Anders Mason
Life of this patent
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Abstract
Apparatus for and method of aligning optical components such as beam splitters in an optical pulse stretcher in which a landing spot of a beam which has traversed a portion of the optical beam splitter and a coincident landing spot of a beam split from a retroreflected input beam are made to align on a target spot. Also disclosed is an apparatus and method for aligning the retroreflector to facilitate proper beam alignment. A fluorescent material may be used to render a beam landing spot visible.
Claims12
A confocal optical pulse stretcher comprising:
- a first concave mirror;
- a second concave mirror confocal with the first concave mirror;
- a retroreflector;
- and
- a beam splitter arranged optically between the first concave mirror and the second concave mirror, the beam splitter being further arranged to split a first beam travelling in a first direction into a first beam portion directed to the first concave mirror and a second beam portion travelling in the first direction, the first beam portion traversing a closed optical path in the confocal optical pulse stretcher, the optical path including a segment between the beam splitter and a landing spot on the second concave mirror, the retroreflector being arranged to retroreflect the second beam portion to produce a retroreflected beam travelling in a second direction opposed to the first direction, the beam splitter being further arranged to split the retroreflected beam into a third beam portion traversing the segment to be incident on the second concave mirror to at least partially overlap with the landing spot.
2 more elements
Apparatus for facilitating alignment of a beam splitter in a confocal optical pulse stretcher,
- the confocal optical pulse stretcher comprising at least a first concave mirror and a second concave mirror confocal with the first concave mirror,
- the confocal optical pulse stretcher additionally comprising a retroreflector,
- the beam splitter being arranged optically between the first concave mirror and the second concave mirror, the beam splitter being further arranged to split a first beam into a first beam portion directed to the first concave mirror and a second beam portion travelling in a first direction toward the retroreflector, the retroreflector being arranged to retroreflect the second beam portion to produce a retroreflected beam,
- the first beam portion traversing an optical path in the confocal optical pulse stretcher, the beam path including a segment between the second concave mirror and the beam splitter,
- the beam splitter being further arranged to split the retroreflected beam into a first portion travelling to the second mirror and a second portion passing through the beam splitter, the apparatus comprising:
- a reflective element having an aperture arranged to receive the second portion of retroreflected beam light passing through the beam splitter and to redirect the light;
- and
- a fluorescent screen arranged to receive the redirected light.
5 more elements
A method of aligning a beam splitter in a confocal optical pulse stretcher,
- the confocal optical pulse stretcher comprising at least a first concave mirror and a second concave mirror confocal with the first concave mirror,
- the beam splitter being arranged optically between a first spot on the first concave mirror and a second spot on the second concave mirror, the beam splitter being further arranged to split a first incoming beam travelling in a first direction into a first beam portion directed to the first spot and a second beam portion continuing to travel in the first direction toward a retroreflector,
- the first beam portion traversing an optical path in the confocal optical pulse stretcher, the optical path including a segment between the second spot and the beam splitter, the first beam portion striking the second mirror at the second spot,
- the method comprising:
- retroreflecting the second beam portion back to the beam splitter along a return path in a second direction opposed to the first direction;
- splitting the retroreflected second beam portion into a beam travelling from the beam splitter to the second spot and a third beam portion continuing to travel in the second direction;
- and
- aligning the split retroreflected second beam portion to be incident on the second mirror at the second spot.
5 more elements
Dependencies are inferred from the claim text.