Device for converting circularly polarized radiation into plane-polarized radiation

Claim 1

A device for converting circularly polarized radiation into plane-polarized radiation having a rotating plane of polarization, comprising a first electro-optic crystal, a second electro-optic crystal, the principle direction of the second electro-optic crystal offset by an angle of approximately 45* with respect to the principle direction of the first electrooptic crystal, means for applying separate modulating voltages in phase-quadrature to the electro-optic crystals, each of the voltages having an amplitude equal to one-half of the amplitude necessary to convert a circularly polarized beam into planepolarized radiation, and a reflector, the electro-optiC crystals and the reflector being aligned to receive a beam of circularly polarized radiation successively passing through the first electro-optic crystal the second electro-optic crystal and reflected back through the two electro-optic crystals in reverse order by the reflector.

Claim 2

A device for converting circularly polarized radiation into plane-polarized radiation having a rotating plane of polarization, comprising a first electro-optic crystal, a second electro-optic crystal, the principle direction of the second electro-optic crystal offset by an angle of approximately 45* with respect to the principle direction of the first electrooptic crystal, means for applying separate modulating voltages in phase-quadrature to the electro-optic crystals, each of the voltages having an amplitude equal to one-half of the amplitude necessary to convert a circularly polarized beam into planepolarized radiation, and a reflector, the electro-optiC crystals and the reflector being aligned to receive a beam of circularly polarized radiation successively passing through the first electro-optic crystal the second electro-optic crystal and reflected back through the two electro-optic crystals in reverse order by the reflector.

Claim 3

A device for producing rotating plane-polarized radiation, comprising means for directing radiation along a linear path, a polarizer in the path of the linear radiation for producing a plane-polarized beam having the same path, a quarter-wave plate having a principle axis offset 45* with respect to the principle axis of the polarizer and placed in the polarized beam for producing circularly polarized radiation, a first electro-optic modulator in the path of the circularly polarized radiation, a second electro-optic modulator in the path of the radiation passing through the first electro-optic modulator, the first and second electro-optic modulators having principle directions offset by an angle of approximately 45* , means for providing the electro-optic modulators with voltages in phase quadrature and having an amplitude equal to one-half the amplitude necessary for the production of rotating plane-polarized radiation, and a reflector in the path of the radiation passing through the second electro-optic modulator for reflecting that radiation back through the second electro-optic modulator the first electro-optic modulator and the quarter-wave plate.

Claim 4

A device for producing rotating plane-polarized radiation, comprising means for directing radiation along a linear path, a polarizer in the path of the linear radiation for producing a plane-polarized beam having the same path, a quarter-wave plate having a principle axis offset 45* with respect to the principle axis of the polarizer and placed in the polarized beam for producing circularly polarized radiation, a first electro-optic modulator in the path of the circularly polarized radiation, a second electro-optic modulator in the path of the radiation passing through the first electro-optic modulator, the first and second electro-optic modulators having principle directions offset by an angle of approximately 45* , means for providing the electro-optic modulators with voltages in phase quadrature and having an amplitude equal to one-half the amplitude necessary for the production of rotating plane-polarized radiation, and a reflector in the path of the radiation passing through the second electro-optic modulator for reflecting that radiation back through the second electro-optic modulator the first electro-optic modulator and the quarter-wave plate.