Ferro-electric azimuth rotator
First Claim
1. An electrically controllable azimuth optical rotator comprising:
- a first quarterwave plate for receiving a first beam of electromagnetic energy having a first arbitrary polarization state, and outputting a second beam in response thereto;
an electric voltage controlled ferro-electric variable phase retarder at approximately 45 degrees to the first quarterwave plate for receiving the second beam and providing a third beam in response thereto, the electric voltage controlled ferro-electric variable phase retarder characterized by a phase shift of 2α
, where α
is a desired angle of rotation of the first arbitrary polarization state; and
a second quarterwave plate aligned either parallel or perpendicular to the first quarterwave plate far receiving the third beam and outputting a fourth beam in response thereto, the fourth beam having a polarization state similar to the first arbitrary polarization state but rotated by α
;
wherein the electric voltage controlled ferro-electric variable phase retarder comprises a plate of transparent polycrystalline PLZT material of a width about (w) 1.44 mm, a length (l) about 1.7 to 2.9 mm. and a height (h) about 500 μ
m. the plate having an optical axis oriented perpendicular to a propagation direction of radiation at a wavelength between 1200 nm and 1600 nm incident upon the plate that has a first polarization state, the plate having electrodes for applying an adjustable electric field between 0 volts and 400 volts across a plane of the plate perpendicular to the propagation direction to provide the phase shift at greater than 2π
such that the polarization of light beam transmitted through the plate is transformed from the first polarization state to a second polarization state having the desired angle of rotation between 0 degrees and 180 degrees.
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Accused Products
Abstract
An electrically controllable azimuth optical rotator (10) includes a first quarterwave plate (16) for receiving a first beam of electromagnetic energy (22) having a first arbitrary polarization state, and outputting a second beam (122) in response to the first quarterwave plate (16). An electric voltage controlled ferro-electric variable phase retarder (20) aligned at approximately 45 degrees to the first quarterwave plate (16) receives the second beam 122 and provides a third beam 38 in response to the retarder (20). The electric voltage controlled ferro-electric variable phase retarder (20) is characterized by a phase shift of φ=2α, where α is a desired angle of rotation of the first arbitrary polarization state. To provide a voltage-controlled rotation, a second quarterwave plate (18) is aligned either parallel or perpendicular to the first quarterwave plate (16) for receiving the third beam (38) and outputting a fourth beam (46) in response to the retarder (20). As a result, the fourth beam (46) has a polarization state similar to the first arbitrary polarization state but rotated by α.
33 Citations
20 Claims
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1. An electrically controllable azimuth optical rotator comprising:
-
a first quarterwave plate for receiving a first beam of electromagnetic energy having a first arbitrary polarization state, and outputting a second beam in response thereto;
an electric voltage controlled ferro-electric variable phase retarder at approximately 45 degrees to the first quarterwave plate for receiving the second beam and providing a third beam in response thereto, the electric voltage controlled ferro-electric variable phase retarder characterized by a phase shift of 2α
, where α
is a desired angle of rotation of the first arbitrary polarization state; and
a second quarterwave plate aligned either parallel or perpendicular to the first quarterwave plate far receiving the third beam and outputting a fourth beam in response thereto, the fourth beam having a polarization state similar to the first arbitrary polarization state but rotated by α
;
wherein the electric voltage controlled ferro-electric variable phase retarder comprises a plate of transparent polycrystalline PLZT material of a width about (w) 1.44 mm, a length (l) about 1.7 to 2.9 mm. and a height (h) about 500 μ
m. the plate having an optical axis oriented perpendicular to a propagation direction of radiation at a wavelength between 1200 nm and 1600 nm incident upon the plate that has a first polarization state, the plate having electrodes for applying an adjustable electric field between 0 volts and 400 volts across a plane of the plate perpendicular to the propagation direction to provide the phase shift at greater than 2π
such that the polarization of light beam transmitted through the plate is transformed from the first polarization state to a second polarization state having the desired angle of rotation between 0 degrees and 180 degrees.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An electrically controllable azimuth optical positive rotator comprising:
-
a first quarterwave plate at approximately 45 degrees for receiving a first light beam having a first arbitrary polarization state, and outputting a second beam in response thereto;
an electric voltage controlled ferro-electric variable phase retarder at approximately 0 degrees for receiving the second beam and providing a third beam in response thereto, the variable phase retarder characterized by a phase shift of 2α
, where a is a desired angle of rotation of the first arbitrary polarization state, wherein the electric voltage controlled ferro-electric variable phase retarder comprises a 9.5/65/35 PLZT hot-pressed bulk ceramic having a width of about 1.44 mm; and
a second quarterwave plate at approximately −
45 degrees for receiving the third beam and outputting a fourth beam in response thereto, the fourth beam having a polarization state similar to the first arbitrary polarization state but rotated by α
.
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18. An electrically controllable azimuth optical negative rotator comprising:
-
a first quarterwave plate at approximately −
45 degrees for receiving a first beam of electromagnetic energy having a first arbitrary polarization state, and outputting a second beam in response thereto;
an electric voltage controlled ferro-electric variable phase retarder at approximately 0 degrees for receiving the second beam and providing a third beam in response thereto, the variable phase retarder characterized by a phase shift of 2α
, where −
α
is a desired angle of rotation of the first arbitrary polarization state, wherein the electric voltage controlled ferro-electric variable phase retarder comprises a 9.5/65/35 PLZT hot-pressed bulk ceramic having a width of about 1.44 mm; and
a second quarterwave plate at approximately −
45 degrees for receiving the third beam and outputting a fourth beam in response thereto, the fourth beam having a polarization state similar to the first arbitrary polarization state but rotated by α
.
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19. An electrically controllable azimuth optical positive rotator comprising:
-
a first quarterwave plate at approximately −
45 degrees for receiving a first beam of electromagnetic energy having a first arbitrary polarization state, and outputting a second beam in response thereto;
an electric voltage controlled ferro-electric variable phase retarder at approximately 0 degrees for receiving the second beam and providing a third beam in response thereto, the variable phase waveplate retarder characterized by a phase shift of 2α
, where −
α
is a desired angle of rotation of the first arbitrary polarization state, wherein the electric voltage controlled ferro-clectric variable phase retarder comprises a 9.5/65/35 PLZT hot-pressed bulk ceramic having a width of about 1.44 mm; and
a second quarterwave plate at approximately −
45 degrees for receiving the third beam and outputting a fourth beam in response thereto, the fourth beam having a polarization state similar to the first arbitrary polarization state but rotated by −
α
.
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20. An electrically controllable azimuth optical negative rotator comprising:
-
a first quartet-wave plate at approximately 45 degrees for receiving a first beam of electromagnetic energy having a first arbitrary polarization state, and outputting a second beam in response thereto;
an electric voltage controlled ferro-electric variable phase retarder at approximately 0 degrees for receiving the second beam and providing a third beam in response thereto, the variable phase waveplate retarder characterized by a phase shift of 2α
, where −
α
is a desired angle of rotation of the first arbitrary polarization state, wherein the electric voltage controlled ferro-electric variable phase retarder comprises a 9.5/65/35 PLZT hot-pressed balk ceramic having a width of about 1.44 mm anda second quarterwave plate at approximately 45 degrees for receiving the third beam and outputting a fourth beam in response thereto, the fourth beam having a polarization state similar to the first arbitrary polarization state but rotated by −
α
.
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Specification