Epitaxial Nd:YLF linear waveguide laser.

Area of Science:

• Optics and Photonics
• Materials Science
• Laser Physics

Background:

• Neodymium-doped yttrium lithium fluoride (Nd:YLF) is a key material for solid-state lasers.
• Waveguide lasers offer advantages in miniaturization and efficiency.
• Liquid-phase epitaxy (LPE) is a versatile crystal growth technique.

Purpose of the Study:

• To demonstrate laser operation in Nd:YLF waveguide structures fabricated by LPE.
• To investigate methods for reducing the threshold pump power in these waveguides.
• To explore the potential of LPE for developing low-threshold upconversion lasers.

Main Methods:

• Fabrication of planar and linear Nd:YLF waveguide structures using liquid-phase epitaxy (LPE).
• Development of ridge-type structures through mechanical polishing and subsequent cladding layer growth.
• Characterization of laser performance, including threshold pump power.

Main Results:

• Achieved laser operation in both planar and linear Nd:YLF waveguides.
• Reduced the threshold pump power from 115 mW in planar waveguides to 8 mW in ridge-type structures.
• Identified scattering and end-face reflection losses as areas for improvement.

Conclusions:

• Ridge-type waveguide structures significantly lower the threshold pump power for Nd:YLF lasers.
• Further optimization of fabrication and reduction of optical losses can lead to even lower thresholds.
• LPE is a promising technique for developing efficient, low-threshold upconversion lasers using various activator ions.