Method and apparatus for modifying a substrate

An apparatus comprising:

• a pulsed laser to generate a pulsed laser beam;
• an arrangement of optical elements to receive at least a portion of the pulsed laser beam, the optical elements comprising:
• a first two-axis beam scanner element;
• and
• a second two-axis beam scanner element after the first two-axis beam scanner element;
• and
• control circuitry to actuate the first two-axis beam scanner element and the second two-axis beam scanner element to control a direction of the pulsed laser beam from laser pulse to laser pulse so that at least three consecutive laser pulses of the pulsed laser beam sequentially irradiate at least three spatial locations according to a predetermined spatial sequence which defines relative spatial positions, and an order of irradiation, of at least three regions of a substrate.

A system comprising:

• a pulsed laser to generate a pulsed laser beam;
• a beamsplitter to receive the pulsed laser beam;
• an arrangement of optical elements to receive a first portion of the pulsed laser beam from the beamsplitter, the optical elements comprising:
• a first two-axis beam scanner element;
• a second two-axis beam scanner element after the first two-axis beam scanner element;
• and
• a microscope objective after the second two-axis beam scanner element;
• a stage to house a substrate, the stage positioned such that a substrate coupled to the stage receives pulsed laser beam from the arrangement of optical elements;
• a photodetector to receive a second portion of the pulsed laser beam;
• and
• control circuitry to actuate the first two-axis beam scanner element and the second two-axis beam scanner element based on signals from the photodetector.

A method comprising:

• generating a pulsed laser beam comprising a train of laser pulses, the train of laser pulses including at least three consecutive laser pulses;
• and
• sequentially irradiating at least three regions of a substrate with the at least three consecutive laser pulses so as to modify the substrate according to a desired spatial profile, wherein modifying the substrate comprises at least one of modifying a refractive index of a material of the substrate, modifying a chemical etchability of the material of the substrate, or ablating the material of the substrate;
• and
• controlling a direction of the pulsed laser beam or a position of the substrate from laser pulse to laser pulse so that the at least three consecutive laser pulses sequentially irradiate the at least three regions of the substrate according to a predetermined spatial sequence which defines relative spatial positions of at least three regions of the substrate and defines an order of irradiation of the at least three regions of the substrate.