Continuous-wave Tm:YAlO₃ laser at ∼2.3  μm

Area of Science:

• Solid-state laser materials
• Quantum electronics
• Materials science

Background:

• Orthorhombic Tm3+:YAlO3 (Thulium-doped Yttrium Aluminum Orthoaluminate) crystals are investigated for laser applications.
• Potential for laser operation at 1.5 μm (H43→F43 transition) and 2.3 μm (H43→H53 transition) has been identified.

Purpose of the Study:

• To characterize the stimulated-emission cross-sections for key transitions in Tm3+:YAlO3.
• To quantify the cross-relaxation processes influencing the upper-laser level lifetime.
• To demonstrate continuous-wave (CW) laser operation at the 2.3 μm transition.

Main Methods:

• Polarized light measurements were used to determine stimulated-emission cross-sections.
• Spectroscopic analysis was performed to quantify cross-relaxation dynamics.
• Continuous-wave laser oscillation was achieved using an a-cut Tm3+:YAlO3 crystal.

Main Results:

• Peak stimulated-emission cross-sections of 0.59×10⁻²⁰ cm² at 1438 nm and 0.80×10⁻²⁰ cm² at 2275 nm were measured for E∥b polarization.
• Cross-relaxation rates affecting the upper-laser level lifetime were quantified.
• Continuous-wave lasing at 2273 nm was successfully demonstrated, producing 254 mW with a slope efficiency of 17.8% and linear polarization (E∥b).

Conclusions:

• The Tm3+:YAlO3 crystal exhibits significant potential for efficient laser operation, particularly at the 2.3 μm transition.
• The measured optical properties and demonstrated CW lasing performance validate Tm3+:YAlO3 as a promising material for mid-infrared laser applications.