Improving performance prediction of diode end-pumped solid-state Nd:YAG rod amplifiers by incorporating pump mode...

Area of Science:

• Laser Physics
• Optical Engineering

Background:

• Master Oscillator Power Amplifier (MOPA) systems are crucial for increasing laser output power.
• Current models often use static approximations for pump beam propagation and neglect spectral shifts.

Purpose of the Study:

• To develop a novel, accurate analytical model for multimode fiber-coupled (FC) pump beams in MOPA systems.
• To incorporate dynamic pump beam evolution and spectral characteristics into MOPA simulations.

Main Methods:

• Modeling multimode FC pump beam emission as a complex field using a phase-only Gaussian to flat-top (FT) diffractive optical element.
• Integrating the pump beam into iterative Fourier beam propagation methods.
• Calibrating the model using experimental measurements of diode emission spectrum.

Main Results:

• Experimental validation using an end-pumped Nd:YAG crystal rod showed excellent agreement between predicted and actual output powers.
• Demonstrated a strong correlation between the Gaussian to FT phase-only transformation and actual multimode FC diode free-space propagation.
• The novel model accurately predicts MOPA performance over a calibrated range of pump powers.

Conclusions:

• The developed model provides a more accurate representation of pump beam dynamics in MOPA systems.
• This approach enhances the predictive capabilities of laser amplifier simulations.
• Accurate modeling is essential for optimizing laser development and performance.