High power handling polarization switches
View Patent ↗Liquid crystal devices are described that maintain performance of polarization/amplitude modulation under high irradiance conditions. Configurations that isolate polarizing elements under high thermal load are discussed which allow other elements, such as glass, which may be sensitive to stress birefringence to remain near optimum thermal conditions.
1. A polarization switch, comprising:
a first assembly operable to receive light, comprising:
a first end cap;
a first polarizer adjacent to the first endcap and located to receive light from the first end cap;
a second end cap adjacent to the first polarizer and located to receive light from the first polarizer;
a second assembly located to receive light from the first assembly, comprising:
a third end cap;
a second polarizer adjacent to the third end cap and located to receive light from the third end cap;
a first cell adjacent to the second polarizer and located to receive light from the second polarizer;
a first compensator located adjacent to the first cell and located to receive light from the first cell;
a second compensators located adjacent to the first compensator and located to receive light from the first compensator;
a second cell adjacent to the second substrate and located to receive light from the second compensator;
a third compensator adjacent to the second cell and located to receive light from the second cell;
a fourth end cap adjacent to the third compensator and located to receive light from the third compensator;
wherein an air gap separates the first assembly from the second assembly.
2. The polarization switch of claim 1 , wherein the first end cap is borofloat glass.
3. The polarization switch of claim 2 , wherein the first end cap comprises an anti-reflective coating.
4. The polarization switch of claim 1 , wherein the first polarizer is a dye polarizer.
5. The polarization switch of claim 1 , wherein the second polarizer is an iodine polarizer.
6. The polarization switch of claim 1 , wherein the first cell and the second cell are liquid crystal cells.
7. The polarization switch of claim 1 , wherein the thickness of the first, second, third and fourth end caps are in the approximate range of 3-12 mm.
8. The polarization switch of claim 1 , wherein the second end cap is synthetic fused silica.
9. The polarization switch of claim 1 , wherein the first, second, and third compensators are —C compensators.
10. The polarization switch of claim 1 , wherein the air gap is in the approximate range of 0.5-10 mm.
11. A high power handling polarization system, comprising:
a first optical assembly operable to receive light, comprising:
a first substrate operable to receive light;
a first polarizer adjacent to the first substrate and operable to receive light from the first substrate;
a planarization layer adjacent to the first polarizer;
a second optical assembly operable to receive light from the first optical assembly, comprising:
a second substrate located to receive light from the planarization layer of the first optical assembly;
a first liquid crystal cell located subsequent in the light path to the second substrate;
a second liquid crystal cell located to receive light from the first liquid crystal cell;
a third substrate located subsequent in the light path to the second liquid crystal cell; and
an air gap located between the first optical assembly and the second optical assembly.
12. The high power handling polarization system of claim 11 , further comprising a second polarizer located to receive light from the second substrate.
13. The high power handling polarization system of claim 12 , wherein the second polarizer is an iodine polarizer.
14. The high power handling polarization system of claim 11 , wherein the first polarizer is an iodine polarizer.
15. The high power handling polarization system of claim 11 , wherein the first second and third end caps further comprise borofloat glass.
16. The high power handling polarization system of claim 11 , wherein the first and second liquid crystal cells further comprise pi-cells.
17. The high power handling polarization system of claim 11 , wherein the thickness of the air gap is in the approximate range of 0.5-10 mm.
18. The high power handling polarization system of claim 11 , wherein the planarization layer is coated with an anti-reflective coating.
19. The high power handling polarization system of claim 11 , wherein the planarization layer is approximately index-matched to the first polarizer substrate.
20. The high power handling polarization system of claim 11 , further comprising a second polarizer, wherein the first polarizer is a dye polarizer and the second polarizer is an iodine polarizer.
21. The high power handling polarization system of claim 11 , further comprising a first and second compensator located between the first and second liquid crystal cells and a third compensator located after the second liquid crystal cell, and before the third end cap.
22. The high power handling polarization system of claim 21 , wherein the first, second, and third compensators are —C compensators.