Patent ID: 6826318
Filing Date: 2004-11-30
Classification: G02B,G02F

Abstract:
A variable polarization plane rotator for rotating a polarization plane of linearly polarized light, comprising:a phase plate that has an optical axis in the same direction as, or at a 90 degree angle relative to, a polarization direction of an input light beam, and applies, to the light beam being transmitted, a 90 degree phase difference between a polarization component parallel to said optical axis and a polarization component perpendicular to said optical axis, a phase difference variable element that has an optical axis at a 45 degree angle relative to the optical axis of said phase plate, and applies, to the light beam being transmitted, a variable phase difference between the polarization component parallel to said optical axis and the polarization component perpendicular to said optical axis, a phase difference adjustment section that adjusts the variable phase difference of said phase difference variable element, and wherein after being transmitted through said phase difference variable element said input light beam is made into an elliptically polarized light or a circularly polarized light, the elliptically polarized light or the circularly polarized light being thereafter transmitted through said phase plate, to thereby be made into a linearly polarized light, so that the polarization plane of said input light beam is rotated by an angle corresponding to the phase difference applied by said phase difference variable element.