Optical materials with selected index-of-refraction
View Patent ↗Photosensitive optical materials are used for establishing more versatile approaches for optical device formation. In some embodiments, unpatterned light is used to shift the index-of-refraction of planar optical structures to shift the index-of-refraction of the photosensitive material to a desired value. This approach can be effective to produce cladding material with a selected index-of-refraction. In additional embodiments gradients in index-of-refraction are formed using, photosensitive materials. In further embodiments, the photosensitive materials are patterned within the planar optical structure. Irradiation of the photosensitive material can selectively shift the index-of-refraction of the patterned photosensitive material. By patterning the light used to irradiate the patterned photosensitive material, different optical devices can be selectively activated within the optical structure.
1. A method for producing a gradient in index-of-refraction in an optical material comprising a photosensitive optical material, the method comprising irradiating the photosensitive optical material to create a light-induced gradient in index-of-refraction, wherein the irradiating of the photosensitive optical material is performed for a selected period of time with light having an intensity and wavelength to induce the gradient in index-of-refraction along the direction of the irradiating, the gradient in index-of-refraction at least about 1×10 −8 index units per micron.
2. The method of claim 1 wherein the optical material comprises a planar optical structure.
3. The method of claim 2 wherein the gradient in index-of-refraction is oriented along the plane of the structure.
4. The method of claim 2 wherein the gradient in index-of-refraction is oriented perpendicular to the plane of the structure.
5. The method of claim 1 wherein the optical material comprises an optical fiber preform or portion thereof with an aspect ratio of at least about 5.
6. The method of claim 1 wherein the photosensitive optical material comprises at least about 1 mole percent germanium as a fraction of the total metal/metalloid content of the photosensitive optical material.
7. The method of claim 1 wherein the light intensity and the composition of the photosensitive material produce absorption of the light in the linear Beer's law regime of spatial variation.
8. The method of claim 1 wherein the light intensity and the composition of the photosensitive material produce absorption of the light with non-linear spatial variation.
9. The method of claim 1 wherein the photosensitive optical material comprises a gradient in composition of a dopant that induces photosensitivity of the material wherein the composition gradient results in the index-of-refraction gradient following illumination.
10. The method of claim 1 wherein the gradient in index-of-refraction extends across a distance of at least about 10 microns.
11. A method for producing a gradient in index-of-refraction in an optical material comprising a photosensitive optical material, the method comprising irradiating the photosensitive optical material to create a light-induced gradient in index-of-refraction, wherein the photosensitive optical material comprises a gradient in composition of a dopant that induces photosensitivity of the material wherein the composition gradient results in the index-of-refraction gradient following the irradiating.
12. The method of claim 11 wherein the optical material comprises a planar optical structure.
13. The method of claim 12 wherein the gradient in index-of-refraction is oriented along the plane of the structure.
14. The method of claim 12 wherein the gradient in index-of-refraction is oriented perpendicular to the plane of the structure.
15. The method of claim 11 wherein the optical material comprises an optical fiber preform or portion thereof with an aspect ratio of at least about 5.
16. The method of claim 11 wherein the photosensitive optical material comprises at least about 1 mole percent germanium as a fraction of the total metal/metalloid content of the photosensitive optical material.
17. The method of claim 11 wherein the irradiating of the photosensitive optical material is performed for a selected period of time with light having an intensity and wavelength to induce the gradient index-of-refraction along the irradiation direction.
18. The method of claim 17 wherein the light intensity and the composition of the photosensitive material produce absorption of the light in the linear Beer's law regime of spatial variation.
19. The method of claim 17 wherein the light intensity and the composition of the photosensitive material produce absorption of the light with non-linear spatial variation.
20. The method of claim 11 wherein the gradient in index-of-refraction extends across a distance of at least about 10 microns.
21. The method of claim 11 wherein the gradient in index-of refraction is at least about 1×10 −8 index units per micron.