Pedagogically fast model to evaluate and optimize passively Q-switched Nd-doped solid-state lasers.

Area of Science:

• Laser Physics
• Quantum Optics
• Nonlinear Optics

Background:

• Passively Q-switched lasers are crucial for generating high-power pulses.
• Accurate modeling of laser dynamics, including spatial effects, is essential for performance optimization.
• Existing models may lack precision in accounting for residual inversion density and high output coupling.

Purpose of the Study:

• To develop a precise analytical model for four-level passively Q-switched lasers.
• To accurately predict output pulse energy and peak power.
• To incorporate the spatial overlap effect and residual inversion density into laser analysis.

Main Methods:

• Coupled rate equations considering spatial overlap were analyzed.
• A transcendental equation for residual inversion density was derived and solved.
• An analytical fitting function was developed for the residual inversion density.
• A pedagogical model incorporating a correction for high output coupling was established.

Main Results:

• An analytical function precisely fitting the residual inversion density was obtained.
• The developed model accurately analyzes output pulse energy and peak power.
• Experimental results validated the predictions of the new analytical model.

Conclusions:

• The derived analytical function and pedagogical model offer a straightforward and accurate method for analyzing passively Q-switched lasers.
• The model's inclusion of spatial overlap and residual inversion density enhances predictive capabilities.
• This work provides a valuable tool for laser design and performance optimization.