Optical material and method for modifying the refractive index
A laser system for modifying the index of refraction of an optical hydrogel material. The laser system comprises a computer program to determine the position and shape of refractive structures to be written into the optical hydrogel material to correct a patient's vision, and a focused laser that generates laser light having a wavelength of from 400 nm to 900 nm, and which operates with an average power of 10 mW to 1000 mW to produce a pulse energy from 0.05 nJ to 1000 nJ with a peak intensity at focus of greater than 10 13 W/cm 2 . The refractive structures exhibit a change in the index of refraction of 0.01 to 0.06 in the optical hydrogel material.
1. A system for making a modified optical device having laser-written refractive structures for correcting a patient's vision, the system comprising:
an optical device to be modified being made of a completely polymerized optical hydrogel material;
a laser system including a laser for emitting a laser beam and a focus objective positioned in proximity to the optical device for focusing the laser beam emitted from the laser within the optical hydrogel material;
the laser beam comprising laser pulses within a wavelength range from 400 nm to 1500 nm, within a pulse energy range from 0.01 nJ to 100 nJ, and within a pulse width range between 4 femtoseconds and 200 femtoseconds;
a compensation scheme including an optical arrangement to compensate for a positive dispersion introduced by the focus objective of the laser system;
the laser system being configured with respect to the optical hydrogel material for generating the laser pulses such that the pulse energy and the pulse width of the pulses comprising the laser beam after having been emitted from the laser impart a pulse peak power at focus positions within the optical hydrogel material which is above a nonlinear absorption threshold of the optical hydrogel material and below an optical breakdown threshold of the optical hydrogel material;
a scanning means of the laser system for relatively moving the optical device and laser beam with respect to each other so that the focus of the laser beam irradiates select regions of the optical hydrogel material; and
the optical hydrogel material being responsive to the incident laser power by undergoing a change in refractive index within the irradiated select regions at which the laser beam is focused within a range of 0.01 to 0.06 while exhibiting little or no scattering loss.
2. The system of claim 1 wherein the irradiated select regions of the optical hydrogel material are defined by an array of discrete cylinders, a series of lines, or a combination of cylinders and a series of lines.
3. The system of claim 1 wherein the irradiated select regions of the optical hydrogel material include volume filled structure arranged as a lens.
4. The system of claim 1 wherein the pulse energy of the laser is from 0.2 nJ to 10 nJ.
5. The system of claim 1 wherein the irradiated select regions of the optical hydrogel material are defined by a series of lines in a two dimensional plane having a width from 0.2 μm to 3 μm and a height from 0.4 μm to 8 μm.
6. The system of claim 1 wherein the irradiated select regions of the optical hydrogel material are defined by a series of lines in a two dimensional plane have a width from 0.6 μm to 1.5 μm, and a height from 1.0 μm to 4 μm.
7. The system of claim 1 wherein the irradiated select regions of the optical hydrogel material are defined by a series of lines forming a line grating.
8. The system of claim 7 wherein the optical hydrogel material has a depth dimension and the line grating is a first of a plurality of line gratings, wherein the first line grating is written at a different depth than a second of the plurality of line gratings.
9. The system of claim 8 wherein the first line grating is oriented substantially orthogonal to the second line grating.
10. The system of claim 1 wherein the irradiated select regions of the optical hydrogel material are defined by an array of dots.
11. The system of claim 1 wherein the irradiated select regions of the optical hydrogel material include a volume-filled three-dimensional lens structure having an overall shape selected from a spheric, an aspheric, a toroidal or a cylindrical shape.
12. The system of claim 1 in which the change in refractive index undergone by regions of the optical hydrogel material is within a range of 0.03 to 0.06.
13. The system of claim 1 wherein the optical device is selected from an intraocular lens, a corneal inlay, a corneal ring or a keratoprothesis.
14. The system of claim 1 in which the optical arrangement of the compensation scheme comprises at least one of a prism, a diffraction grating, a chirped mirror, and a dispersion compensating mirror to compensate for the positive dispersion introduced by the focus objective.