Optical material and method for modifying the refractive index
A method for modifying the refractive index of an optical, polymeric material. The method comprises irradiating select regions of the optical, polymeric material with a focused, visible or near-IR laser having a pulse energy from 0.05 nJ to 1000 nJ. The irradiation results in the formation of refractive optical structures, which exhibit little or no scattering loss. The method can he used to modify the refractive index of an intraocular lens following the surgical implantation of the intraocular lens in a human eye. The invention is also directed to an optical device comprising refractive optical structures, which exhibit little or no scattering loss and are characterized by a positive change in refractive index.
1. An optical device comprising an optical polymeric material with select regions that have been irradiated with a focused, femtosecond laser having a wavelength from 400 nm to 1500 nm, wherein the optical polymeric material is a hydrogel and the irradiated regions are formed inside the optical material and are characterized by a change in refractive index of 0.01 to 0.06 and exhibit low scattering, wherein the irradiated regions are formed at multiple depths in the optical material, and wherein the optical device is selected from a contact lens, an intraocular lens, a corneal inlay, a corneal ring or a keratoprothesis.
2. The optical device of claim 1 wherein the optical, polymeric material is a completely polymerized, optical material.
3. The optical device of claim 1 wherein the irradiated regions of the optical material include features arranged in a plane.
4. The optical device of claim 1 wherein the irradiated regions include features arranged in planes at different depths of the optical material.
5. The optical device of claim 1 wherein the irradiated regions include at least one array of dots in which the individual dots exhibit a refractive index difference from their surrounding optical polymeric material.
6. The optical device of claim 1 wherein the irradiated regions of the optical material include a grating structure.
7. The optical device of claim 6 wherein the grating structure is a line grating.
8. The optical device of claim 7 in which the line grating has a grating line width of one micron and a thickness of three microns.
9. The optical device of claim 1 wherein the change in refractive index in at least a portion of the irradiated regions is from 0.03 to 0.06.
10. The optical device of claim 1 wherein the change in refractive index in at least a portion of the irradiated regions is a positive change in refractive index.
11. The optical device of claim 1 wherein the optical polymeric material is prepared from (meth)acrylate monomer.
12. The optical device of claim 1 wherein the optical device is a contact lens.
13. The optical device of claim 1 in which the irradiated regions are irradiated with a beam from the femtosecond laser and have an elliptical cross-sectional shape with a longer of two axes oriented in the direction of the laser beam.
14. The optical device of claim 1 , wherein the select regions have been irradiated with a focused, femtosecond laser having a pulse width of less than 200 fs.