Cholesteric liquid crystal structure
A liquid crystal optical device that includes a first substrate layer that is substantially flat and a second substrate layer that is substantially flat and parallel to the first substrate layer. The liquid crystal optical device further includes a layer of cholesteric liquid crystal disposed between the first substrate layer and the second substrate layer, where the layer of cholesteric liquid crystal is arranged in domains, each domain having a helical axis, wherein the helical axes of the domains have a plurality of orientations relative to an orientation of the first and second substrate layers, and where a wavefront of a light wave having a wavelength within a range of wavelengths changes after reflecting from the layer of cholesteric liquid crystal.
1. A method for reflecting light from a liquid crystal optical device, comprising:
applying a voltage across a first electrode and a second electrode, wherein a layer of cholesteric liquid crystal is disposed between the first electrode and the second electrode, wherein the cholesteric liquid crystal comprises a plurality of domains, each domain having a helical axis, the helical axes of the plurality of domains having different orientations, wherein the different orientations are configured to cause the layer of cholesteric liquid crystal to act as a positive or negative lens with respect to a range of wavelengths such that light within the range of wavelengths incident upon the first substrate layer is reflected by the layer of cholesteric liquid crystal in a converging or diverging manner; and
varying the voltage to modify a degree of convergence or divergence caused by the layer of cholesteric liquid crystal;
wherein the layer of cholesteric liquid crystal is substantially flat.
2. The method according to claim 1 , wherein at least one of the first electrode and the second electrode is transparent, and the layer of cholesteric liquid crystal changes state based on varying the voltage.
3. The method according to claim 1 , wherein the liquid crystal optical device comprises two layers of cholesteric liquid crystal, wherein the two layers of cholesteric liquid crystal have the same handedness or opposite handedness.
4. The method according to claim 3 , wherein the liquid crystal optical device comprises a layer of birefringent material disposed between the two layers of cholesteric liquid crystal.
5. The method according to claim 3 , wherein the first electrode is disposed on a first substrate layer that is substantially flat, and the second electrode is disposed on a second substrate layer that is substantially flat.