Technique for photodisruptive multi-pulse treatment of a material

Patent metadata

Field	Value
Publication number	US-10159602-B2
Application number	US-201414785826-A
Country	US
Kind code	B2
Filing date	May 7, 2014
Priority date	May 7, 2014
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

Abstract

Embodiments of the invention provide a method and apparatus for laser-processing a material. In the embodiments, a diffraction-limited beam of pulsed laser radiation is diffracted by a diffraction device to generate a diffracted beam. The diffracted beam is subsequently focused onto the material and is controlled in time and space to irradiate the material at a target position with radiation from a set of radiation pulses of the diffracted beam so that each radiation pulse from the set of radiation pulses is incident at the target position with a cross-sectional portion of the diffracted beam, the cross-sectional portion including a local intensity maximum of the diffracted beam. The beam cross-sectional portions of at least a subset of the pulses of the set include each a different local intensity maxi-mum. In this way, a multi-pulse application for generating a photo-disruption at a target location of the material can be implemented.

First claim

The invention claimed is:

1. An apparatus for laser-processing a material, the apparatus comprising:
a laser source configured to provide a diffraction-limited beam of pulsed laser radiation;
a diffraction device configured to diffract the diffraction-limited beam to generate a diffracted beam comprising a set of radiation pulses, each pulse having a plurality local intensity maxima where at least two local intensity maxima have different intensity values;
a focusing objective configured to focus the diffracted beam onto the material; and
a controller configured to control the diffracted beam to irradiate the material at a target position with a cross-sectional portion of the diffracted beam, the cross-sectional portion including the local intensity maxima of the radiation pulses, the controlling comprising directing each radiation pulse towards the target position with the cross-sectional portion in order to distribute the local intensity maxima of the radiation pulse across the material.

2. The apparatus of claim 1 , wherein the beam cross-sectional portions are distinct when projected onto a transverse plane.

3. The apparatus of claim 1 , wherein at least one pair of the beam cross-sectional portions are partially overlapping when projected onto a transverse plane.

4. The apparatus of claim 1 , wherein the diffracted beam has a point distribution of the local intensity maxima in a focal area of the beam.

5. The apparatus of claim 4 , wherein the point distribution is a two-dimensional distribution.

6. The apparatus of claim 5 , wherein the two-dimensional distribution is one of a matrix distribution and a distribution based on concentric circles.

7. The apparatus of claim 4 , wherein:
at least a subset of the local intensity maxima of the diffracted beam are distributed along a line, and
the controller is configured to control the diffracted beam to move the beam over the target position in the direction of the line.

8. The apparatus of claim 4 , wherein:
the controller is configured to control the diffracted beam to move the beam across the material transversely with respect to a beam propagation direction in accordance with a predetermined shot pattern to generate a photo-disruption at each of a plurality of shot positions defined by the shot pattern, and
a distance between adjacent shot positions corresponds to a distance between adjacent local intensity maxima of the point distribution.

9. The apparatus of claim 1 , wherein the local intensity maxima include two or more maxima of substantially equal intensity value.

10. The apparatus of claim 1 , wherein each local intensity maximum of the diffracted beam is below a single-pulse intensity threshold for a laser-induced optical breakdown in human eye tissue.

11. The apparatus of claim 1 , wherein the radiation from a temporally last pulse in the set of radiation pulses has highest intensity among the set.

12. The apparatus of claim 1 , wherein spatially adjacent local intensity maxima of the diffracted beam have a distance of less than 20 μm in a focal area of the beam.

Assignees

• Wavelight Gmbh

Inventors

• Vogler Klaus
• Donitzky Christof

Classifications

• A61F2009/00897

  Scanning mechanisms or algorithms · CPC title

• H01S3/005

  Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping (shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B) · CPC title

• A61F2009/00872

  Cornea · CPC title

• A61B18/20

  using laser · CPC title

• A61F9/00825

  for photodisruption · CPC title