Beam multiplexer for writing refractive index changes in optical materials

Abstract

A refractive index writing system includes a pulsed laser source, an objective lens for focusing an output of the pulsed laser source to a focal spot in an optical material, and a scanner for relatively moving the focal spot with respect to the optical material along a scan region. A beam multiplexer divides the output of the laser source into at least two working beams that are focused to variously shaped focal spots within the optical material. A controller controls at least one of a temporal and a spatial offset between the focal spots of the working beams together with the relative speed and direction of the scanner for maintaining an energy profile within the optical material along the scan region above a nonlinear absorption threshold of the optical material and below a breakdown threshold of the optical materials.

Description

technical field [0001] This application relates to the use of pulsed lasers to alter the refractive index of optical media, and in particular to writing refractive index changes into ocular tissue or replacing or augmenting structures to alter or enhance a patient's visual performance. Background technique [0002] It has been demonstrated that a pulsed laser operating in a specified range that is particularly suitable for the target optical material can produce localized refractive index changes in the optical material without damaging the material in a way that impairs vision. While above the nonlinear absorption threshold, the energy range is often just below the destruction threshold of optical materials, where significant light scattering or absorption degrades the optical material's expected performance. Considerations for these appropriate energy ranges include pulse wavelength, pulse energy, pulse duration, size and shape to focus the pulse into the optical material,...

AI Technical Summary

Problems solved by technology

Constraints related to the need to deliver the concentrated pulse energy of a laser beam in a form that achieves the desired refractive index change in the optical material without exceeding the damage threshold at which the desired optical properties are degraded limit the possibilities for writing the refractive index change into the optical material. speed and efficiency

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