High-efficiency KYW acousto-optic Q-switch for a Ho:YAG laser.

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Acousto-optic Q-switches are crucial for pulsed laser operation.
• Developing efficient Q-switches for specific wavelengths, like 2.1 μm, is an ongoing challenge.

Purpose of the Study:

• To develop a novel acousto-optic Q-switch using potassium yttrium tungstate (KYW) crystal.
• To characterize the performance and laser-induced damage threshold of the new Q-switch.

Main Methods:

• Utilized the slow shear acoustic mode in KYW crystal for Q-switch fabrication.
• Designed two Q-switch configurations for vertical and horizontal light polarization.
• Measured diffraction efficiency, RF driving power, and laser-induced damage threshold.

Main Results:

• Achieved over 50% diffraction efficiency at 2.1 μm with RF power below 8 W.
• Determined a laser-induced damage threshold of 650 MW/cm² for the KYW crystal.
• Successfully operated a nanosecond periodically pulsed Ho:YAG laser using the developed KYW Q-switch.

Conclusions:

• The novel KYW acousto-optic Q-switch is effective for 2.1 μm laser applications.
• The high damage threshold and efficiency make KYW a promising material for high-power Q-switched lasers.