Diode-end-pumped room temperature Tm,Ho:YLF lasers.

Area of Science:

• Laser physics
• Solid-state lasers
• Quantum optics

Background:

• Thulium and holmium-doped lasers are crucial for various applications, including spectroscopy and medical treatments.
• Efficient room-temperature operation of these lasers is highly desirable but presents significant challenges.
• Understanding and mitigating loss mechanisms like upconversion and re-absorption is key to improving laser performance.

Purpose of the Study:

• To demonstrate room-temperature continuous-wave (CW) and Q-switched operation of Tm,Ho:YLF lasers.
• To investigate the efficiency and output characteristics of end-pumped Tm,Ho:YLF lasers.
• To analyze the performance limitations and theoretical aspects of Tm,Ho:YLF laser operation.

Main Methods:

• Utilized a 3W CW laser diode for end-pumping a Tm,Ho:YLF crystal.
• Incorporated two intra-cavity solid etalons for single-frequency operation.
• Employed acousto-optic modulation for Q-switched operation.
• Developed analytical formulas to model threshold pump power and slope efficiency, accounting for energy transfer upconversion and ground state re-absorption.

Main Results:

• Achieved 393mW of CW 2-micrometer laser output with 14% optical-to-optical efficiency.
• Obtained 113mW of single-frequency output with a low threshold power of 250mW.
• Generated Q-switched laser pulses with 45µJ energy and 142ns FWHM pulse width at 1.7W pump power.
• Validated experimental results with theoretical analysis incorporating key loss mechanisms.

Conclusions:

• Demonstrated efficient room-temperature CW and Q-switched operation of Tm,Ho:YLF lasers.
• The single-frequency output is suitable for use as a seed laser.
• The theoretical model provides valuable insights into optimizing Tm,Ho:YLF laser performance by considering upconversion and re-absorption.