Phased-Array Beam Steering for High-Rate Laser Micromachining
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Solution Overview
Problem
Existing laser-micromachining processes face challenges with spatially overlapping pulses leading to negative effects like local heat accumulation and pulse-plume interaction, necessitating beam steering systems with higher positioning bandwidths than what acousto-optic deflectors and polygon mirrors can provide.
Innovation Solution
A multi-channel beam splitter and phase modulator array within a photonic integrated circuit (PIC) system that splits and phase-modulates laser signals, combined with an optical amplifier and harmonic conversion module, enabling high-bandwidth beam steering and shaping of laser pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high repetition rate laser pulses (1 MHz-100 MHz) are used, then productivity is improved, but pulse spatial separation becomes difficult to maintain
Solution Approach 1:
The invention segments the laser beam into multiple parallel beams using a beam splitter array, allowing each beam to be independently directed to different spatial locations. This enables maintenance of pulse separation even at high repetition rates by distributing pulses across multiple spatial channels rather than relying on temporal separation alone.
Solution Approach 2:
The invention transitions from one-dimensional temporal pulse separation to two-dimensional spatial-temporal separation by using phased-array beam steering. Multiple beams are steered across different angular positions and focal points, creating spatial separation in addition to temporal separation, which enables precise feature formation at high repetition rates.
2Speed
If acousto-optic deflectors (AODs) are used for beam steering, then positioning bandwidth is improved (～1 MHz), but device complexity and cost increase
Solution Approach 1:
The invention merges multiple beam steering functions into a single phased-array system that combines beam splitting, phase modulation, and directional control. By integrating these functions into one coherent system rather than using separate AODs or polygon mirrors for each beam, the overall device complexity is reduced while maintaining high positioning bandwidth.
Solution Approach 2:
The invention replaces mechanical beam steering systems (polygon mirrors, galvanometers) with a phased-array optical system that uses phase modulation and interference patterns to achieve beam steering. This substitution eliminates moving parts and mechanical complexity while achieving comparable or superior positioning bandwidth.
3Manufacturing precision
If pulses are spatially separated to prevent heat accumulation, then manufacturing precision is improved, but productivity decreases due to lower repetition rates
Solution Approach 1:
The invention segments the laser energy into multiple parallel beams that can be directed to adjacent features simultaneously. This allows spatial separation of pulses for precision work while maintaining high repetition rates for productivity, as multiple features are processed in parallel rather than sequentially.
Solution Approach 2:
The invention uses periodic phase modulation to steer beams between different feature locations in a controlled sequence. By implementing periodic beam steering patterns that return to home positions, the system maintains precise spatial separation for accuracy while operating at high repetition rates for productivity.
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
Enables efficient, high-precision beam steering and shaping of laser pulses at GHz bandwidths, allowing for accurate material processing with reduced heat accumulation and improved feature formation.
Implementation Method 1
a multi-channel beam splitter arranged and configured to split an input first optical signal into a plurality of split first optical signals
Implementation Method 2
a plurality of phase modulators, wherein each phase modulator of the plurality of phase modulators is operative to modify a phase of a corresponding split first optical signal
Implementation Method 3
a waveguide arranged at an optical output of the plurality of phase modulators, the waveguide configured to spatially-rearrange the split first optical signals output from the plurality of phase modulators
Implementation Method 4
an optical amplifier arranged at an optical output of the waveguide, the optical amplifier configured to amplify the first optical signal pattern produced by the waveguide
Implementation Method 5
a harmonic conversion module disposed within a beam path along which the laser beam is propagatable after transmission though the lens, wherein the harmonic conversion module is operative to convert the first wavelength of the laser beam to a second wavelength
Data Source
AI summary
A system includes a multi-channel beam splitter arranged and configured to split an input optical signal into a plurality of split optical signals; a plurality of phase modulators, wherein each phase modulator of the plurality of phase modulators is operative to modify a phase of a corresponding split optical signal of the plurality of split optical signals in response to a control signal; a waveguide arranged at an optical output of the plurality of phase modulators, the waveguide configured to spatially-rearrange the split optical signals output from the plurality of phase modulators into a pattern, thereby producing an optical signal pattern; and an optical amplifier arranged at an optical output of the waveguide, wherein the optical amplifier is configured to amplify the optical signal pattern produced by the waveguide.