US4790634A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bistable liquid crystal in a fabry-perot etalon
Assignee: UK Secretary of State for Defence
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Filing: 1987-09-04
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Granted: 1988-12-13
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Expires: 2007-09-04
Abstract
Abstract An optically bistable device comprises a Fabry-Perot etalon containing intracavity liquid crystal material. Etalon mirros of deposited silver are overlaid on indium tin oxide electrodes. The electrodes provide electrical biasing means for the material, which exhibits both optical nonlinearity and electro-optic tunability of refractive index. The etalon has an interference fringe maximum at a wavelength λ m1 . the fringe is tunable to λ m2 by applying a bias voltage across the mirrors. A light beam illuminates the etalon, the beam having a wavelength λ s where λ m2 is between λ s and λ m1 . The beam intensity is sufficient to induce bistable etalon switching for a fringe at λ m2 but not for a fringe at λ m1 . Tuning the etalon fringe electro-optically from λ m1 to λ m2 initiates optical bistability without the prior art requirement of either variable light intensity or an external electrical feedback loop.
Inventors
- 👤 Alan Miller
- 👤 Jacqueline Staromlynska
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:13
CPC Classifications
G; G02; G02F; G02F3/00; G02F3/02; G02F3/022; G02F1/00; G02F1/01; G02F1/21; G02F1/216; G02F3/024
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
142 words
An optically bistable device including a Fabry-Perot etalon containing intracavity optically nonlinear material and arranged to exhibit optical bistability, and wherein: (1) the cavity material refractive index is electro-optically tunable via etalon biassing means to move an etalon interference fringe maximum from a wavelength λ m1 to a wavelength λ m2 , (2) a light source having a wavelength λ s is arranged to pass light through the etalon, where λ m2 lies between λ m1 and λ s , λ s and the source intensity being arranged to initiate optical bistability at an etalon fringe wavelength of λ m2 but to be inappropriate for bistability at a fringe wavelength of λ m1 , and (3) the etalon biassing means are connected to a variable voltage source arranged at least for etalon fringe maximum tuning from λ m1 to λ m2 .
Claim 2
Dependent Claim
142 words
An optically bistable device including a Fabry-Perot etalon containing intracavity optically nonlinear material and arranged to exhibit optical bistability, and wherein: (1) the cavity material refractive index is electro-optically tunable via etalon biassing means to move an etalon interference fringe maximum from a wavelength λ m1 to a wavelength λ m2 , (2) a light source having a wavelength λ s is arranged to pass light through the etalon, where λ m2 lies between λ m1 and λ s , λ s and the source intensity being arranged to initiate optical bistability at an etalon fringe wavelength of λ m2 but to be inappropriate for bistability at a fringe wavelength of λ m1 , and (3) the etalon biassing means are connected to a variable voltage source arranged at least for etalon fringe maximum tuning from λ m1 to λ m2 .
Claim 3
Dependent Claim
54 words
A device according to claim 1 wherein the etalon cavity material has an optical nonlinearity parameter n 2 at least equal to 10 -6 cm 2 /Watt and an electro-optic coefficient and thickness appropriate for cavity phase tuning through at least a bistable loop in response to a bias voltage change of 10 Volts.
Claim 4
Dependent Claim
22 words
A device according to claim 2 wherein the cavity material is a liquid crystal material having a birefringence of at least 0.05.
Claim 5
Dependent Claim
16 words
A device according to claim 3 wherein the birefringence is in the range 0.09 to 0.11.
Claim 6
Dependent Claim
37 words
A device according to claim 3 or 4 wherein the cavity material is optically absorbing to a degree sufficient to effect temperature rise as required for optical bistability, and the etalon mirrors are of dielectric multilayer construction.
Claim 7
Dependent Claim
19 words
A device according to claim 1 having partially absorbing etalon mirrors to effect temperature rise and produce optical bistability.
Claim 8
Dependent Claim
17 words
A device according to claim 1 wherein the etalon cavity material is a multiple quantum well structure.
Claim 9
Independent Claim
129 words
A method of obtaining optical bistability including the steps of: (1) providing a Fabry-Perot etalon arranged for optical bistability and containing intracavity optically nonlinear material, the cavity material refractive index being electro-optically tunable via etalon biassing means to move an etalon interference fringe maximum from a wavelength λ m1 to a wavelength λ m2 , (2) illuminating the etalon with light having a wavelength λ s , where λ m2 lies between λ m1 and λ s , λ s and the light intensity being arranged to initiate bistability at an etalon fringe wavelength of λ m2 but to be inappropriate for bistability at a fringe wavelength of λ m1 , and (3) altering etalon bias to produce etalon fringe maximum tuning from λ m1 to λ m2 .
Claim 10
Independent Claim
129 words
A method of obtaining optical bistability including the steps of: (1) providing a Fabry-Perot etalon arranged for optical bistability and containing intracavity optically nonlinear material, the cavity material refractive index being electro-optically tunable via etalon biassing means to move an etalon interference fringe maximum from a wavelength λ m1 to a wavelength λ m2 , (2) illuminating the etalon with light having a wavelength λ s , where λ m2 lies between λ m1 and λ s , λ s and the light intensity being arranged to initiate bistability at an etalon fringe wavelength of λ m2 but to be inappropriate for bistability at a fringe wavelength of λ m1 , and (3) altering etalon bias to produce etalon fringe maximum tuning from λ m1 to λ m2 .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-12-13 | 1992-06-13 | 1992-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-13 | 1996-06-13 | 1996-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-13 | 2000-06-13 | 2000-12-13 | $7700.00 | Window Closed / Lapsed |