Efficient all-solid-state passively Q-switched SWIR Tm:YAP/KGW Raman laser.

Area of Science:

• Laser Physics
• Nonlinear Optics
• Solid-State Lasers

Background:

• The 2 µm spectral region is crucial for various applications, including medical procedures and remote sensing.
• Developing efficient and compact laser sources in this region remains a significant challenge.
• Passive laser configurations offer advantages in simplicity and robustness compared to active systems.

Purpose of the Study:

• To demonstrate an efficient, all-passive Raman laser operating in the 2 µm spectral regime.
• To investigate the performance of a KGW (KAlGe4O12) crystal in a Raman laser setup.
• To achieve high output energy and conversion efficiency using a passive configuration.

Main Methods:

• An external-cavity configuration was employed for the KGW Raman laser.
• The laser was pumped by a passively Q-switched Tm:YAP laser operating at 1935 nm.
• The bi-axial properties of the KGW crystal were utilized to generate stimulated Raman emission.

Main Results:

• Stimulated Raman emission was observed at two distinct spectral lines: 2272 nm and 2343 nm.
• Output energies of 340 µJ/pulse and 450 µJ/pulse were achieved at 2272 nm and 2343 nm, respectively.
• Seed-to-Raman laser conversion efficiencies of 19.2% and 23.5% were obtained, rivaling actively Q-switched systems.

Conclusions:

• This work presents the first demonstration of an efficient, all-passive Raman laser in the 2 µm spectral regime.
• The developed passive KGW Raman laser offers a promising alternative to complex active laser systems.
• The high efficiencies achieved highlight the potential of passive configurations for generating 2 µm radiation.