Spatial modification of a Gaussian beam on reflection from a saturable absorber

Area of Science:

• Nonlinear optics
• Atomic and molecular physics
• Surface science

Background:

• Calculating reflection coefficients is crucial for understanding light-matter interactions.
• Nonlinear optical phenomena in gases require advanced theoretical models.
• The slowly varying amplitude approximation is often insufficient for dense media.

Purpose of the Study:

• To determine the reflection coefficient of a dielectric-gas interface.
• To incorporate nonlinear local field, saturation, and self-reflected wave effects.
• To analyze reflectivity changes induced by incident light intensity.

Main Methods:

• Developing a theoretical framework for dielectric-gas interfaces.
• Specializing calculations for collisionally broadened gases.
• Analyzing the transverse profile changes of reflected Gaussian beams.

Main Results:

• The reflection coefficient is influenced by nonlinear local field, saturation, and self-reflected waves.
• Effective aperturing effects in amplitude and phase were identified.
• Reflectivity dependence on incident field intensity was demonstrated.

Conclusions:

• The study provides a model for nonlinear reflection at dielectric-gas interfaces.
• Nonlinear effects significantly alter the reflected beam profile.
• The findings are relevant for understanding light propagation in dense optical media.