Tm,Ho:YLF waveguide lasers at 2.05 µm

Area of Science:

• Laser Physics
• Materials Science
• Photonics

Background:

• Mid-infrared lasers are crucial for various applications, including spectroscopy and medical treatments.
• Developing compact and efficient mid-infrared laser sources remains a significant challenge.
• Thulium and holmium-doped crystals are promising gain media for mid-infrared emission.

Purpose of the Study:

• To report the first 2.05-micrometer laser based on femtosecond-laser direct written (FsLDW) Tm,Ho:YLF cladding waveguides.
• To investigate the lasing performance of the fabricated waveguide.
• To explore the influence of cavity conditions and pump light polarization on laser output.

Main Methods:

• Fabrication of a channel waveguide in a Tm,Ho:YLF crystal using femtosecond-laser direct writing (FsLDW).
• The waveguide featured a 90-µm diameter low-index cladding for fiber-like guidance.
• Characterization of the laser performance, including output power, threshold, and slope efficiency, under Ti:sapphire laser pumping.

Main Results:

• Efficient lasing oscillation was achieved at 2050 nm.
• Maximum output power reached 47.5 mW with a slope efficiency of 20.1%.
• A low lasing threshold of 181 mW was observed, indicating high efficiency.

Conclusions:

• The study successfully demonstrated the first 2.05-µm laser using FsLDW Tm,Ho:YLF cladding waveguides.
• The results highlight the potential of FsLDW technology for creating compact and durable mid-infrared lasers.
• Further optimization of cavity conditions and pump parameters can enhance laser performance.