Methods and systems for coherent imaging and feedback control for modification of materials
AssigneeIPG Phontonics
InventorsPaul J. L. Webster, James M. Fraser, Victor X. D. Yang
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Abstract
Methods and systems are provided for using optical interferometry in the context of material modification processes such as surgical laser or welding applications. An imaging optical source that produces imaging light. A feedback controller controls at least one processing parameter of the material modification process based on an interferometry output generated using the imaging light. A method of processing interferograms is provided based on homodyne filtering. A method of generating a record of a material modification process using an interferometry output is provided.
Claims26
An apparatus comprising:
- a material processing beam source that produces a material processing beam that is applied to at least one location of a material in a material modification process;
- an imaging optical source that produces imaging light;
- wherein the material processing beam and the imaging light share at least one optical element comprising a mirror;
- an optical interferometer that produces an interferometry output using at least a component of the imaging light that is delivered to the material, at least a component of the interferometry output simultaneously including reflections of the component of the imaging light from at least first and second optical path lengths to the material;
- the interferometry output based on a comparison of at least two optical path lengths to the material, wherein the at least two optical path lengths are compared (i) to each other, or (ii) to another optical path length, or (iii) both (i) and (ii);
- a detector that receives the interferometry output and produces a detector output that is indicative of a characteristic of the material before, during, or after the material modification process;
- and
- an image processor that receives the detector output and at least tracks material geometry to establish a reference optical path length to the material.
A method for monitoring, controlling, or monitoring and controlling at least one processing parameter of a material modification process, the method comprising:
- generating imaging light with an imaging optical source;
- applying a material processing beam to a location of a material in the material modification process;
- wherein the material processing beam and the imaging light share at least one optical element comprising a mirror;
- producing an interferometry output using at least a component of the imaging light that is delivered to the material, at least a component of the interferometry output simultaneously including reflections of the component of the imaging light from at least first and second optical path lengths to the material;
- the interferometry output based on a comparison of at least two optical path lengths to the material, wherein the at least two optical path lengths are compared (i) to each other, or (ii) to another optical path length, or (iii) both (i) and (ii);
- detecting the interferometry output and producing a detector output that is indicative of a characteristic of the material before, during, or after the material modification process;
- and
- using the detector output to track material geometry and establish a reference optical path length to the material.
Dependencies are inferred from the claim text.