Coherent Imaging Feedback for Axial Control in Laser Material Processing
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Solution Overview
Problem
Current laser technologies face challenges in achieving precise axial control during material processing, particularly in medical and industrial applications, due to limitations in controlling the depth of laser beam penetration, leading to issues such as unintended tissue damage and weld porosity.
Innovation Solution
An apparatus and method utilizing an optical interferometer to generate an interferometry output based on optical path lengths, which is used to control processing parameters of the material modification process, enabling real-time feedback and precise control of the material processing beam's depth penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard metrology techniques are used to guide laser processing, then quality assurance data can be obtained, but plasma generation and electrical interference interfere with the measurement
Solution Approach 1:
The patent introduces an optical interferometer as an intermediary measurement tool that uses light instead of electrical signals to probe the material, thereby avoiding interference from plasma generation and electrical noise while still providing precise depth measurements
Solution Approach 2:
The system replaces electrical-based metrology techniques with optical-based interferometry, substituting the measurement mechanism to eliminate susceptibility to electrical interference and plasma effects during laser processing
2Ease of operation
If laser processing is used for medical surgeries, then high transverse control and non-contact operation are achieved, but axial control is poor leading to unintended tissue damage
Solution Approach 1:
The patent implements real-time feedback control using optical interferometry to monitor axial penetration depth during laser surgery, automatically adjusting processing parameters to maintain precise depth control and prevent unintended tissue damage
Solution Approach 2:
The system performs preliminary opto-thermal characterization of the tissue to determine the relationship between laser parameters and penetration depth, storing this information for use during surgery to achieve precise axial control without requiring extensive surgeon experience
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for precise control of the material processing depth, improving the accuracy and reliability of laser-based surgeries and industrial processes by providing real-time feedback and reducing the risk of unintended damage or porosity.
Implementation Method 1
an optical interferometer that produces an interferometry output using at least a component of the imaging light that is delivered to the sample, the interferometry output based on at least one optical path length to the sample compared to another optical path length
Data Source
AI summary
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.