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US 7,009,711 B2Granted
Retroreflector coating for an interferometer
AssigneeZygo Corporation
InventorHenry A. Hill
Life of this patent
Estimating the term…
Abstract
A corner cube retroreflector having a coating including one or more layers at each reflecting surface. The coating causes the retroreflector to have polarization eigenstates that are substantially linear and to have the properties of a half-wave plate. The coated retroreflector can be used in interferometry and microlithography system.
Claims44
An apparatus comprising:
- a corner cube retroreflector comprising three mutual perpendicular reflecting surfaces, the corner cube retroreflector defining a body diagonal;
- and
- a coating at each of the reflecting surfaces, the coating comprising at least one layer,
- wherein, for each of the reflecting surfaces, the coating causes a relative phase retardation ε, defined by the phase angle in radians between p and s reflection coefficients at the reflecting surface, to be substantially equal to π with respect to a plane of incidence including a normal to the reflecting surface and the body diagonal.
1 more element
An apparatus comprising:
- a corner cube retroreflector comprising three mutual perpendicular reflecting surfaces, the corner cube retroreflector defining a body diagonal;
- and
- a coating at each of the reflecting surfaces, the coating comprising at least one layer,
- wherein the coating on each of the reflecting surfaces causes the corner cube retroreflector to have polarization eigenstates that are substantially linear, and to have a relative phase retardation δ due to the combined effect of the three reflecting surfaces that has a first and a second derivative with respect to a relative phase retardation ε that are each substantially less than π, where ε is a relative phase retardation at each reflecting surface, defined by the phase angle in radians between p and s reflection coefficients at the reflecting surface, with respect to a plane of incidence including a normal to the reflecting surface and the body diagonal.
1 more element
Dependencies are inferred from the claim text.