Polarization-modulating optical element
AssigneeCarl Zeiss SMT GmbH
InventorsDamian Fiolka, Markus Deguenther
Life of this patent
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Abstract
A polarization-modulating optical element formed of an optically active crystal material has a thickness profile where the thickness, as measured in the direction of the optical axis, varies over the area of the optical element. The polarization-modulating optical element has the effect that the plane of oscillation of a first linearly polarized light ray and the plane of oscillation of a second linearly polarized light ray are rotated, respectively, by a first angle of rotation and a second angle of rotation, with the first angle of rotation and the second angle of rotation being different from each other.
Claims16
An optical element, comprising:
- a polarization-modulating optical element comprising an optically active crystal having an optical axis, the polarization-modulating optical element having a thickness profile that, as measured in the direction of the optical axis, is variable,
- wherein the polarization-modulating optical element is configured to transform an entering light bundle with a first linear polarization distribution into an exiting light bundle with a second linear polarization distribution different from the first linear polarization distribution, and the second linear polarization distribution is an approximately tangential polarization distribution, and
- wherein the polarization-modulating optical element comprises at least two planar-parallel portions of different thickness or different optical effective thickness.
An optical element, comprising:
- a polarization-modulating optical element comprising an optically active crystal having an optical axis, the polarization-modulating optical element having a thickness profile that, as measured in the direction of the optical axis, is variable,
- a first group of substantially planar-parallel portions;
- and
- a second group of substantially planar-parallel portions,
- wherein:
- the polarization-modulating optical element is configured to transform an entering light bundle with a first linear polarization distribution into an exiting light bundle with a second linear polarization distribution different from the first linear polarization distribution, and the second linear polarization distribution is an approximately tangential polarization distribution,
- when linearly polarized light passes through the optical element, a plane of oscillation of the linearly polarized light is rotated by a first angle of rotation β1 by the first group of substantially planar-parallel portions,
- when linearly polarized light passes through the optical element, a plane of oscillation of the linearly polarized light is rotated by a second angle of rotation β2 by the second group of substantially planar-parallel portions, and
- β1 and β2 are approximately conforming to the expression |β2−β1|=(2n+1)·90°, with n representing an integer having a value that is greater than or equal to zero.
Dependencies are inferred from the claim text.