Structural and optical behavior due to thermal effects in end-pumped Yb:YAG disk lasers

Area of Science:

• Laser physics and materials science
• Computational modeling and simulation

Background:

• End-pumped continuous-wave (CW) Yb:YAG disk lasers are crucial for high-power applications.
• Inhomogeneous thermal, stress, and strain distributions significantly degrade laser performance.
• These distributions lead to detrimental effects like disk fracture, birefringence, and thermal lensing.

Purpose of the Study:

• To predict the optical and structural behavior of end-pumped CW Yb:YAG disk lasers.
• To investigate the impact of thermal and mechanical stresses on laser performance.
• To analyze the dependence of optical phase distortion on key operational parameters.

Main Methods:

• Utilized a Monte Carlo ray-tracing code for optical analysis.
• Employed the ANSYS package for structural and thermal simulations.
• Investigated distributions of temperature, stress, and strain within the laser medium.

Main Results:

• Identified inhomogeneous temperature, stress, and strain as primary causes of deleterious effects.
• Demonstrated that thermal lensing is a significant contributor to optical phase distortion.
• Quantified the influence of heat transfer coefficient, cooling fluid temperature, and crystal thickness on optical phase distortion.

Conclusions:

• Accurate prediction of optical and structural behavior is essential for optimizing Yb:YAG disk lasers.
• Thermal lensing and associated optical phase distortion are critical factors limiting laser performance.
• Understanding parameter dependencies allows for mitigation strategies to improve laser efficiency and stability.