Liquid crystal waveguide having refractive shapes for dynamically controlling light
Liquid crystal waveguides for dynamically controlling the refraction of light. Generally, liquid crystal materials may be disposed within a waveguide in a cladding proximate or adjacent to a core layer of the waveguide. In one example, portions of the liquid crystal material can be induced to form refractive or lens shapes in the cladding that interact with a portion (e.g. evanescent) of light in the waveguide so as to permit electronic control of the refraction/bending, focusing, or defocusing of light as it travels through the waveguide. In one example, a waveguide may be formed using one or more patterned or shaped electrodes that induce formation of such refractive or lens shapes of liquid crystal material, or alternatively, an alignment layer may have one or more regions that define such refractive or lens shapes to induce formation of refractive or lens shapes of the liquid crystal material. In another example, such refractive or lens shapes of liquid crystal material may be formed by patterning or shaping a cladding to define a region or cavity to contain liquid crystal material in which the liquid crystal materials may interact with the evanescent light.
1. A waveguide for controllably refracting a light beam, comprising:
a substantially planar core defining a substantially planar upper surface, the core operable to guide the light beam through the waveguide in a direction parallel to the substantially planar upper surface;
at least one cladding having a liquid crystal material therein;
at least one alignment layer adjacent to the at least one cladding, the alignment layer operable to orient the liquid crystal material in an initial orientation;
at least one electrode for receiving at least one voltage; and
at least one non-normal interface within the waveguide, the non-normal interface operable to receive the light beam at an angle and to refract the light beam by an amount that is controlled by the voltage, thereby forming a refracted light beam, wherein the angle is larger than a total internal reflection angle such that at least a portion of the refracted light beam traverses the non-normal interface;
wherein the refracted light beam is operable to propagate in a direction parallel to the substantially planar upper surface of the core.
2. The waveguide of claim 1 , wherein the light beam has an evanescent portion, and wherein the liquid crystal material in the cladding interacts with the evanescent portion of the light beam to control refraction of the light beam.
3. The waveguide of claim 1 , wherein the at least one cladding includes an upper cladding and a lower cladding, the upper cladding having the liquid crystal material disposed therein.
4. The waveguide of claim 1 , wherein the at least one cladding includes an upper cladding and a lower cladding, the lower cladding having the liquid crystal material disposed therein.
5. The waveguide of claim 1 , wherein at least a portion of the liquid crystal material in said at least one cladding defines at least one refractive shape, said one refractive shape having an index of refraction controlled by the at least one voltage applied to the at least one electrode.
6. The waveguide of claim 1 , wherein at least a portion of the liquid crystal material in said at least one cladding defines a first refractive shape and a second refractive shape in series controlled by the at least one voltage applied to the at least one electrode.
7. The waveguide of claim 1 , wherein at least a portion of the liquid crystal material in said at least one cladding defines at least a first refractive shape and at least a second refractive shape in series controlled by the voltage applied to the at least one electrode, the first refractive shape being different from the second refractive shape.
8. The waveguide of claim 1 , wherein at least a portion of the liquid crystal material in said at least one cladding defines a lens shape controlled by the voltage applied to the at least one electrode.
9. The waveguide of claim 1 , wherein the core includes a silicon oxynitride material.
10. The waveguide of claim 1 ,wherein the liquid crystal material is a nemetic material.
11. The waveguide of claim 1 , wherein the voltage is an AC voltage.
12. The waveguide of claim 1 , wherein the at least one electrode includes a conductive film layer.
13. The waveguide of claim 1 , wherein the at least one electrode includes a p-doped silicon substrate.
14. The waveguide of claim 1 , wherein the light beam is a TM polarized light beam and travels through the waveguide along a propagation axis; and
wherein the liquid crystal material is orientated with its long axis substantially parallel to the propagation axis when the voltage is approximately zero, and the liquid crystal material is oriented with its long axis tilted relative to the propagation axis when the voltage is non-zero such that the TM polarized light beam is controllably refracted in the waveguide based on the voltage.
15. The waveguide of claim 1 , wherein the light beam is a TE polarized light beam and travels through the waveguide along a propagation axis; and
wherein the liquid crystal material is orientated with its long axis tilted at a first angle relative to the propagation axis when the voltage is approximately zero, and the liquid crystal material is oriented with its long axis tilted at a second angle relative to the propagation axis when the voltage is non-zero such that the TE polarized light beam is controllably refracted in the waveguide based on the voltage.
16. The waveguide of claim 1 , wherein the light beam is a TM polarized light beam and travels through the waveguide along a propagation axis; and
wherein the liquid crystal material is orientated with its long axis tilted at a first angle relative to the propagation axis when the voltage is approximately zero, and the liquid crystal material is oriented with its long axis tilted at a second angle relative to the propagation axis when the voltage is non-zero such that the TM polarized light beam is controllably refracted in the waveguide based on the voltage.
17. The waveguide of claim 1 , wherein the at least one electrode defines at least one refractive shape.
18. The waveguide of claim 1 , wherein the voltage includes a first voltage and a second voltage; and wherein the at least one electrode includes a first electrode for receiving the first voltage and a second electrode for receiving the second voltage.
19. The waveguide of claim 18 , wherein the first electrode defines a first refractive shape and the second electrode defines a second refractive shape, and wherein the first and second voltages are independent.
20. The waveguide of claim 1 , wherein the at least one electrode includes an upper electrode and a lower electrode.
21. The waveguide of claim 20 , wherein the upper electrode includes at least one refractive shape.
22. The waveguide of claim 20 , wherein the upper electrode includes a lens shape.
23. The waveguide of claim 20 , wherein the upper electrode includes a wedge shape.
24. The waveguide of claim 20 , wherein the lower electrode includes a p-doped silicon substrate.
25. The waveguide of claim 20 , wherein the lower electrode includes a refractive shape.
26. The waveguide of claim 1 , wherein the at least one cladding has an upper surface and a lower surface, and wherein the at least one alignment layer is an upper alignment layer adjacent the upper surface of the at least one cladding.
27. The waveguide of claim 26 , wherein the upper alignment layer initially biases an orientation of said liquid crystal material.
28. The waveguide of claim 1 ,
wherein the at least one cladding includes an upper cladding and a lower cladding, the upper cladding having the liquid crystal material disposed therein, the upper cladding having an upper and lower surface;
wherein the at least one electrode includes an upper electrode and a lower electrode, the upper electrode including a refractive shape and the lower electrode defining a plane; and
wherein the at least one alignment layer is an upper alignment layer adjacent the upper surface of the upper cladding.
29. The waveguide of claim 28 , wherein the lower cladding is positioned below the core, the lower alignment layer is positioned above the core and below the lower surface of the upper cladding, the upper alignment layer is positioned above the upper surface of the upper cladding and below the upper electrode.
30. The waveguide of claim 1 ,
wherein the at least one cladding includes an upper cladding and a lower cladding, the upper cladding having the liquid crystal material disposed therein, the upper cladding having an upper and tower surface;
wherein the at least one electrode includes an upper electrode and a lower electrode, the lower electrode including a refractive shape and the upper electrode defining a plane; and
wherein the at least one alignment layer is an upper alignment layer adjacent the upper surface of the upper cladding.
31. The waveguide of claim 30 , wherein the lower electrode is positioned below the lower cladding, the lower cladding is positioned below the core, the lower alignment layer is positioned above the core and below the lower surface of the upper cladding, the upper alignment layer is positioned above the upper surface of the upper cladding and below the upper electrode.
32. The waveguide of claim 1 , wherein the alignment layer has at least a first region biasing said liquid crystal material in a first orientation, and the alignment layer has a second region biasing said liquid crystal material in a second orientation, said second region defining at least one refractive shape.
33. The waveguide of claim 32 , wherein when the voltage is applied to the at least one electrode, the first orientation of the liquid crystal material in the first region changes, and the second orientation of the liquid crystal material in the second region changes, thereby altering an amount of refraction of the light beam in the waveguide.
34. The waveguide of claim 32 , wherein the light beam travels through the waveguide along a propagation axis, and
wherein the first orientation is substantially perpendicular to the propagation axis, and the second orientation is substantially parallel to the propagation axis.
35. The waveguide of claim 32 , wherein the second region includes at least one wedge shape defined therein.
36. The waveguide of claim 32 , wherein the second region includes at least one lens shape defined therein.
37. The waveguide of claim 32 , wherein the at least one cladding includes an upper and lower cladding, the lower cladding is positioned below the core, the alignment layer is positioned above the core and below the upper cladding, and the upper electrode is positioned above the upper cladding.
38. The waveguide of claim 1 , wherein the at least one cladding includes a cavity defined therein, said cavity containing the liquid crystal material disposed therein, said cavity defining at least one refractive shape.
39. The waveguide of claim 38 , wherein the cavity includes at least one wedge shape defined therein.
40. The waveguide of claim 38 , wherein the cavity includes at least one lens shape defined therein.
41. The waveguide of claim 1 ,
wherein the at least one cladding includes an upper cladding and a lower cladding, the upper cladding having an upper surface and a lower surface, the upper cladding having a cavity defined therein, said cavity containing the liquid crystal material, the cavity includes at least one refractive shape defined therein;
wherein the at least one electrode includes an upper electrode and a lower electrode; and
wherein the at least one alignment layer is an upper alignment layer adjacent the upper surface of the upper cladding.
42. The waveguide of claim 41 , wherein the liquid crystal material in the cavity has an index of refraction, and when the voltage is applied to the at least one electrode, the index of refraction of the liquid crystal material in the cavity changes, thereby altering an amount of refraction of the light beam in the waveguide.
43. The waveguide of claim 41 , wherein the lower cladding is positioned below the core, the lower alignment layer is positioned above the core, and the upper alignment layer is positioned above the upper surface of the upper cladding and below the upper electrode.
44. A waveguide, comprising:
a substantially planar core defining a substantially planar lower surface, the core operable to guide a light beam through the waveguide in a direction parallel to the substantially planar lower surface;
at least one cladding having a liquid crystal material within at least a portion of said cladding wherein at least a portion of the liquid crystal material forms one or more refractive shapes having an index of refraction;
at least one alignment layer adjacent the at least one cladding, the alignment layer operable to orient the liquid crystal material in an initial orientation; and
at least one electrode;
wherein as a voltage is applied to said electrode, the index of refraction of the one or more refractive shapes is altered to controllably refract the light beam as it travels through the waveguide, wherein the refraction of the light beam is confined to be in a direction substantially parallel to the substantially planar lower surface of the core.
45. The waveguide of claim 44 , wherein the light beam has an evanescent portion, and wherein the liquid crystal material in the at least one cladding interacts with the evanescent portion of the light beam to control refraction of the light beam.
46. The waveguide of claim 44 , wherein the at least one electrode defines at least one refractive shape.
47. The waveguide of claim 44 , wherein the at least one voltage includes a first voltage and a second voltage; and wherein the at least one electrode includes a first electrode for receiving the first voltage and a second electrode for receiving the second voltage.
48. The waveguide of claim 47 , wherein the first electrode defines a first refractive shape and the second electrode defines a second refractive shape, and wherein the first and second voltages are independent.
49. The waveguide of claim 44 , wherein the at least one alignment layer has at least a first region biasing said liquid crystal material in a first orientation, and has a second region biasing said liquid crystal material in a second orientation, said second region defining at least one or more refractive shapes.
50. The waveguide of claim 44 , wherein the at least one cladding includes a cavity defined therein, said cavity containing the liquid crystal material disposed therein, said cavity defining at least one or more refractive shapes.
51. A waveguide for steering a light beam, comprising:
a substantially planar core defining a substantially planar upper surface, the core operable to guide the light beam through the waveguide in a direction parallel to the substantially planar upper surface;
at least one cladding having a liquid crystal material disposed therein, said cladding having a first region characterized by a first index of refraction and a second region characterized by a second index of refraction;
at least one interface oriented non-orthogonally to the direction of propagation of the light beam, the interface positioned within the waveguide between the first region and the second region, the interface operable to receive the light beam at an angle and operable to steer the light beam thereby forming a steered light beam, wherein the angle is larger than the total internal reflection angle such that at least a portion of the steered light beam transmits through the interface;
at least one alignment layer adjacent the at least one cladding, the alignment layer operable to orient the liquid crystal material in an initial orientation; and
at least one electrode;
wherein at least the second index of refraction is controlled by a voltage applied to the electrode, thereby steering the steered light beam in a direction parallel to the substantially planar upper surface.
52. The waveguide of claim 51 , wherein the light beam has an evanescent portion, and wherein the liquid crystal material in the at least one cladding interacts with the evanescent portion of the light beam to control an amount of steering of the light beam.
53. The waveguide of claim 51 , wherein at least a portion of the liquid crystal material in said at least one cladding defines at least one refractive shape, said refractive shape having an index of refraction controlled by the voltage applied to the at least one electrode.
54. The waveguide of claim 51 , wherein the at least one electrode defines at least one refractive shape.
55. The waveguide of claim 51 , wherein the at least one voltage includes a first voltage and a second voltage; and wherein the at least one electrode includes a first electrode for receiving the first voltage and a second electrode for receiving the second voltage.
56. The waveguide of claim 55 , wherein the first electrode defines a first refractive shape and the second electrode defines a second refractive shape, and wherein the first and second voltages are independent.
57. The waveguide of claim 51 , wherein the at least one alignment layer has at least a first region biasing said liquid crystal material in a first orientation, and the alignment layer has a second region biasing said liquid crystal material in a second orientation, said second region defining at least one refractive shape.
58. The waveguide of claim 51 , wherein the at least one cladding includes a cavity defined therein, said cavity containing the liquid crystal material disposed therein, said cavity defining at least one refractive shape.
59. A waveguide for refracting a light beam, comprising:
a substantially planar core defining a substantially planar upper surface;
at least one cladding having a liquid crystal material disposed therein, said cladding having at least a first region that includes at least a portion of the liquid crystal material having a first orientation, wherein the first region has at least a leading edge and a trailing edge;
at least one alignment layer adjacent the at least one cladding, the alignment layer operable to orient the liquid crystal material in an initial orientation; and
at least one electrode;
wherein the first orientation of the first portion of the liquid crystal material in the at least first region selectively changes from a first state to a second state based on a voltage applied to said electrode thereby refracting the light beam in a direction parallel to the substantially planar upper surface of the core, and wherein the light beam when refracted traverses the trailing edge of the first region.
60. The waveguide of claim 59 , wherein the light beam has an evanescent portion, and wherein at least a portion of the liquid crystal material in the at least one cladding interacts with the evanescent portion of the light beam to control refraction of the light beam.
61. The waveguide of claim 59 , wherein at least a portion of the liquid crystal material in said at least one cladding defines at least one refractive shape, said refractive shape having an index of refraction controlled by the voltage applied to the at least one electrode.
62. The waveguide of claim 59 , wherein the at least one electrode defines at least one refractive shape.
63. The waveguide of claim 59 , wherein the voltage includes a first voltage and a second voltage; and wherein the at least one electrode includes a first electrode for receiving the first voltage and a second electrode for receiving the second voltage.
64. The waveguide of claim 63 , wherein the first electrode defines a first refractive shape and the second electrode defines a second refractive shape, and wherein the first and second voltages are independent.
65. The waveguide of claim 59 , wherein the at least one alignment layer has at least a first region biasing said liquid crystal material in a first orientation, and the alignment layer has a second region biasing said liquid crystal material in a second orientation, said second region defining at least one refractive shape.
66. The waveguide of claim 59 , wherein the at least one cladding includes a cavity defined therein, said cavity containing the liquid crystal material disposed therein, said cavity defining at least one refractive shape.