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, comprising:
a substantially planar core for guiding a light beam through the waveguide, wherein said planar core has a thickness of less than one half a wavelength of the light beam, wherein the core has an index of refraction sized such that a TE index is not equal to a TM index for an operable voltage range of 0 to 100 V to avoid TE and TM crossings;
at least one cladding having a liquid crystal material disposed therein; and
means for controllably refracting the light beam in a direction parallel to said planar core as the light beam travels through the waveguide.
2. The waveguide of claim 1 , wherein the means for controllably refracting includes:
at least one electrode for receiving at least one voltage, said electrode defines at least one refractive shape;
wherein the light beam is refracted by an amount that is controlled by the at least one voltage.
3. The waveguide of claim 1 , wherein at least a portion of the liquid crystal material forms one or more refractive shapes having an index of refraction; and
the means for controllably refracting includes 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.
4. The waveguide of claim 1 , wherein said cladding has a first region characterized by a first index of refraction and a second region characterized by a second index of refraction; and
wherein the means for controllably refracting includes at least one electrode;
wherein at least the second index of refraction is controlled by a voltage applied to the electrode.
5. The waveguide of claim 1 , wherein said cladding has at least a first region that includes at least a portion of the liquid crystal material having a first orientation; and
the means for controllably refracting includes 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.
6. The waveguide of claim 1 , wherein the liquid crystal material is comprised of a superfluorinated liquid crystal.
7. The waveguide of claim 1 , wherein the liquid crystal material has a birefringence greater than 0.1.
8. The waveguide of claim 1 , wherein the thickness of the planar core is sized such that the index of refraction of the waveguide changes by at least 0.01 over a range of 0 to 50 V.