Order parameter description of walk-off effect on pattern selection in degenerate optical parametric oscillators

Area of Science:

• Nonlinear optics
• Laser physics

Background:

• Degenerate optical parametric oscillators (DOPOs) exhibit complex dynamics.
• The walk-off effect significantly influences pattern formation in nonlinear optical systems.

Purpose of the Study:

• To investigate the nonlinear dynamics and pattern selection in DOPOs under the influence of the walk-off effect.
• To model the behavior of translating fronts in DOPOs near the oscillation threshold.

Main Methods:

• Derivation of a real convective Swift-Hohenberg equation to describe the system's dynamics.
• Comparison of theoretical predictions with numerical solutions of the fundamental DOPO equations.

Main Results:

• The real convective Swift-Hohenberg equation effectively captures the main characteristics of the walk-off effect on pattern selection.
• Uniformly translating fronts and nonuniformly translating envelope fronts are observed.
• Excellent quantitative agreement between the model's predictions and numerical simulations for selected wave vector and instability threshold.

Conclusions:

• The developed Swift-Hohenberg model provides a robust framework for understanding walk-off effects in DOPOs.
• The findings offer insights into controlling pattern selection and stability in nonlinear optical systems.