Radiation-balanced lasing in Yb³⁺:YAG and Yb³⁺:KYW

Area of Science:

• Laser Physics
• Materials Science
• Optical Engineering

Background:

• Yb-doped laser crystals are crucial for various applications.
• Thermal management is critical for efficient laser operation.
• Previous studies suggested impurity absorption hinders radiation-balanced lasing.

Purpose of the Study:

• To demonstrate and analyze radiation-balanced lasing in Yb-doped laser crystals at room temperature.
• To achieve high laser efficiency and precise thermal control.
• To investigate the role of background impurity absorption in radiation-balanced lasers.

Main Methods:

• Experimental setup for Yb-doped YAG and Yb-doped KYW lasers.
• Frequency-locking the laser cavity to the input light.
• Thermal profiling and analysis including background impurity absorption saturation.

Main Results:

• Record 30.5% efficiency achieved in 3% Yb³⁺:YAG with temperature deviations within 0.1 K.
• Radiation-balanced lasing demonstrated in 2% Yb³⁺:KYW with 2.2% efficiency, despite impurities and optical losses.
• Quantitative agreement between theoretical models and experimental data, with impurity absorption saturation included.

Conclusions:

• Impure gain media can be successfully operated as radiation-balanced lasers.
• The findings challenge previous predictions by highlighting the importance of impurity properties.
• Radiation-balanced lasing offers a viable path for efficient, thermally stable laser operation.