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Harmonic Nanoparticles for Regenerative Research
Published on: May 1, 2014
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Higher-order nonlinearities revisited and their effect on harmonic generation.
Darshana L Weerawarne1, Xiaohui Gao2, Alexander L Gaeta2
1Department of Physics, Applied Physics and Astronomy, Binghamton University, State University of New York, Binghamton, New York 13902, USA.
Physical Review Letters
|March 21, 2015
Summary
Higher-order nonlinearities in air do not significantly defocus high-power laser filaments. Plasma formation is the primary defocusing mechanism, though nonlinear effects impact harmonic generation phase matching.
Area of Science:
- Nonlinear Optics
- Laser-Plasma Interactions
- Quantum Optics
Background:
- The higher-order Kerr effect model predicts nonlinear optical phenomena in gases.
- Understanding nonlinearities is crucial for high-power laser propagation and harmonic generation.
Purpose of the Study:
- To experimentally test the higher-order Kerr effect model in air.
- To investigate the role of higher-order nonlinearities in high-power laser filamentation and harmonic generation.
Main Methods:
- Performing harmonic generation experiments in air.
- Conducting theoretical calculations to model nonlinear optical effects.
- Analyzing defocusing mechanisms and phase matching conditions.
Main Results:
- Fifth-order nonlinearity in air is non-negligible but has a small overall defocusing effect.
- Plasma formation is identified as the dominant defocusing mechanism in high-power filamentation.
- Higher-order nonlinearities significantly influence the phase matching for harmonic generation.
Conclusions:
- The higher-order Kerr effect model requires refinement for high-power filamentation in air.
- Plasma dynamics play a more critical role in defocusing than previously assumed.
- Nonlinear optical effects, including higher-order ones, are essential for controlling harmonic generation.
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