Modeling of beam width in passively Q-switched end-pumped lasers

Area of Science:

• Laser physics
• Nonlinear optics
• Optical resonators

Background:

• Understanding laser resonator dynamics is crucial for optimizing laser performance.
• Saturable gain and absorption significantly influence pulse buildup and beam characteristics.
• Existing models often simplify the complex interactions within resonators.

Purpose of the Study:

• To develop an iterative model for estimating fundamental mode parameters in resonators with saturable gain guiding.
• To analyze the pulse buildup process in passively Q-switched, end-pumped lasers.
• To investigate the impact of spatially variable saturated gain and absorption bleaching on beam width.

Main Methods:

• Development of an iterative model utilizing the LambertW function.
• Calculation of the effective ABCD cavity matrix for successive round-trips.
• Inclusion of spatially variable saturated gain and absorption bleaching effects.

Main Results:

• The model accurately estimates fundamental mode parameters for resonators with saturable gain guiding.
• A twofold decrease in beam width was demonstrated compared to the fundamental mode of a bare cavity.
• The analysis provided insights into pulse buildup dynamics in passively Q-switched lasers.

Conclusions:

• The developed iterative LambertW function-based model is effective for analyzing laser resonators with nonlinear elements.
• The findings demonstrate a significant improvement in beam confinement.
• The model's applicability can be extended to resonators with other nonlinear optical elements.