Channel waveguide lasers in bulk Tm:LiYF₄ produced by deep diamond-saw dicing

Area of Science:

• Materials Science
• Photonics
• Laser Technology

Background:

• Fabricating integrated optical devices in bulk crystals is challenging.
• Existing methods often lack precision for high-aspect-ratio structures.
• Waveguides are crucial for miniaturizing and enhancing laser systems.

Purpose of the Study:

• To introduce a novel method for fabricating deep channel waveguides in bulk crystals.
• To demonstrate the waveguiding and laser performance of these fabricated channels.
• To assess the applicability of this method to other laser crystal materials.

Main Methods:

• Utilized precision diamond saw dicing to create high-aspect-ratio channels in Tm3+:LiYF4 crystals.
• Characterized channel dimensions and surface roughness using confocal laser microscopy.
• Evaluated waveguiding properties at ~815 nm and laser operation at ~1.91 µm.

Main Results:

• Fabricated channels with depths of 200 µm and widths of 10-50 µm.
• Achieved low wall roughness (<100 nm RMS) and efficient mode confinement.
• Demonstrated quasi-continuous wave laser operation with 0.68 W peak power and 53.3% slope efficiency.

Conclusions:

• Precision diamond saw dicing is an effective technique for fabricating deep waveguides in laser crystals.
• The fabricated waveguides support efficient laser operation with low propagation losses.
• This method shows broad applicability for developing integrated photonic devices in various rare-earth doped crystals.