Liquid crystal phase modulator using cholesteric circular polarizers
AssigneeBoard of Regents of the University of Colorado
InventorsGary D. Sharp, Jay E. Stockley, Kristina M. Johnson
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Abstract
This invention provides a phase modulator comprising an electro-optically rotatable smectic liquid crystal half-wave retarder in combination with a cholesteric liquid crystal circular polarizer. Rotation of the half-wave retarder varies the phase delay of the modulator. A polarizing interferometer is provided utilizing the phase modulator of this invention in combination with a second cholesteric circular polarizer and a linear polarizer. A tunable Fabry-Perot resonator which does not require ordinary mirrors is provided utilizing the phase modulator of this invention in combination with a second cholesteric circular polarizer.
Claims36
A device comprising at least one liquid crystal optical modulator for receiving incident light, wherein said incident light can comprise first and second circularly polarized components of opposite handedness, wherein a first modulator consists essentially of:
- a first smectic liquid crystal half-wave retarder having a rotatable optic axis, for modulating the phase of the light as a function of the orientation of said optic axis of said liquid crystal;
- electric field means for rotating said optic axis of said first smectic liquid crystal half-wave retarder;
- a first cholesteric liquid crystal circular polarizer of a first handedness, optically coupled with said first smectic liquid crystal half-wave retarder;
- and
- a second cholesteric liquid crystal circular polarizer of a second handedness, positioned on the opposite side of said first smectic liquid crystal half-wave retarder from said first cholesteric circular polarizer;
- wherein said first cholesteric circular polarizer, said second cholesteric circular polarizer and said first liquid crystal half-wave retarder form a resonance cavity for said first circularly polarized component of said incident light and do not form a resonance cavity for said second circularly polarized component of said incident light.
A liquid crystal optical modulator for receiving incident light, wherein said incident light comprises first and second circularly polarized components of opposite handedness, comprising:
- a first smectic liquid crystal half-wave retarder having a rotatable optic axis, for modulating the phase of the light as a function of the orientation of said optic axis of said liquid crystal;
- electric field means for rotating said optic axis of said first smectic liquid crystal half-wave retarder;
- a first cholesteric liquid crystal circular polarizer of a first handedness, optically coupled with said first smectic liquid crystal half-wave retarder;
- and
- a second cholesteric liquid crystal circular polarizer of a second handedness, positioned on the opposite side of said first smectic liquid crystal half-wave retarder from said first cholesteric circular polarizer;
- wherein said first cholesteric circular polarizer, said second cholesteric circular polarizer and said first liquid crystal half-wave retarder form a resonance cavity for said first circularly polarized component of said incident light and do not form a resonance cavity for said second circularly polarized component of said incident light;
- and
- wherein said first liquid crystal half-wave retarder is not part of another resonance cavity for said second circularly polarized component of said incident light.
Dependencies are inferred from the claim text.