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Aberration-induced vortex splitting in amplified orbital angular momentum beams
Optics Express
|June 29, 2023
Summary
Researchers amplified higher-order orbital angular momentum (OAM) beams using a compact Nd:YAG laser system. They mitigated wavefront aberrations to achieve high vortex purity and significant amplification for structured light applications.
Area of Science:
- Laser Physics
- Optics
- Photonics
Background:
- Master-Oscillator-Power-Amplifier (MOPA) designs are crucial for high-power laser applications.
- Orbital Angular Momentum (OAM) beams offer unique properties for structured light applications.
- Thermal aberrations in laser crystals can degrade beam quality.
Purpose of the Study:
- To generate and amplify higher-order (l=2) OAM beams using a compact Nd:YAG MOPA.
- To analyze and mitigate thermally-induced wavefront aberrations affecting OAM beam quality.
- To achieve high vortex purity and amplification enhancement for structured light.
Main Methods:
- Utilized a compact end-pumped Nd:YAG MOPA design.
- Employed Shack-Hartmann wavefront sensing to analyze thermal aberrations.
- Applied modal decomposition to characterize the OAM field.
- Engineered the Gouy phase in the far field to correct aberrations.
Main Results:
- Demonstrated the generation and amplification of l=2 OAM beams.
- Identified natural astigmatism in the Nd:YAG crystal causing vortex phase singularity splitting.
- Achieved an amplified vortex purity of 94% after aberration correction.
- Obtained an amplification enhancement of up to 1200%.
Conclusions:
- The study successfully generated and amplified higher-order OAM beams with high purity.
- Engineering the Gouy phase effectively mitigates thermal aberrations in Nd:YAG MOPA systems.
- The findings are valuable for high-power structured light applications in communications and materials processing.
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