Efficient KY1-x-yGdxLuy(WO4)2:Tm3+ channel waveguide lasers

Area of Science:

• Materials Science
• Optoelectronics
• Laser Physics

Background:

• Potassium gadolinium tungstate (KGW) and related compounds are promising host materials for solid-state lasers.
• Doping with rare-earth ions like Gadolinium (Gd3+), Lutetium (Lu3+), and Thulium (Tm3+) can tailor optical properties.
• Waveguide fabrication is crucial for miniaturized and integrated photonic devices.

Purpose of the Study:

• To develop and characterize GdLmTm-co-doped KY(WO4)2 channel waveguides.
• To investigate the laser performance and optical properties of these waveguides.
• To explore wavelength tunability in the mid-infrared region.

Main Methods:

• Liquid-phase epitaxy (LPE) for growing GdLmTm-doped KY(WO4)2 layers.
• Ar+-beam milling for microstructuring ridge-type channel waveguides.
• Overgrowth with pure KY(WO4)2 for cladding.
• Laser experiments utilizing butt-coupled dielectric mirrors.

Main Results:

• Waveguides with low propagation loss (~0.11 dB/cm) were achieved.
• Maximum output powers of 149 mW (TM) and 76 mW (TE) were demonstrated.
• Slope efficiencies reached 31.5% (TM) and 17.0% (TE) with a low threshold of 7 mW.
• Laser wavelength was tunable from 1930 nm to 1846 nm.

Conclusions:

• GdLmTm-co-doped KY(WO4)2 waveguides are suitable for efficient mid-infrared laser applications.
• The fabrication method allows for low-loss waveguide structures.
• Tunable laser output is achievable, offering flexibility for various applications.