Optical Kerr effect field measurements and ad hoc engineering model comparisons

Area of Science:

• Nonlinear Optics
• Atmospheric Optics
• Laser Physics

Background:

• Optical Kerr effects from high peak-power laser beams in atmospheres are well-studied.
• Predicting filamentation onset and light channel formation remains a challenge.

Purpose of the Study:

• To propose a novel analytical model for predicting filamentation/light channel onset distance in real atmospheres.
• To quantify the radius of light channels formed by self-focusing, with and without plasma filamentation.

Main Methods:

• Developed an analytical model based on modulation instability.
• Utilized a weighted ratio of Gaussian beam diameter to lateral coherence radius.
• Incorporated atmospheric absorption and turbulence into the model.

Main Results:

• The model predicts normalized intensity growth as an exponential function of propagation distance.
• Onset distance predictions are compared with computer simulations and field experiments.
• Theoretical radius calculations are compared to measurements from 1.5-micron USPL field experiments.

Conclusions:

• The proposed model offers a new analytical approach to understanding laser beam propagation and filamentation in real atmospheres.
• The model provides a method to estimate beam collapse distance and light channel radius.
• Experimental validation supports the model's predictive capabilities for atmospheric laser propagation.