Compact high-power MIR laser through pulse fiber laser pumped PPMgLN-based OPO

Area of Science:

• Photonics
• Laser Physics
• Nonlinear Optics

Background:

• Mid-infrared (MIR) lasers are crucial for spectroscopy, sensing, and medical applications.
• High-power and compact MIR sources are in demand but challenging to develop.
• Existing OPO systems often suffer from complexity and thermal lensing at high powers.

Purpose of the Study:

• To present a compact and high-power mid-infrared laser system.
• To demonstrate efficient power conversion from a fiber laser to MIR output.
• To achieve high beam quality in the MIR output.

Main Methods:

• Utilized a gain-switched pulse fiber laser amplifier (40 W max power) as a pump source.
• Employed a periodically poled magnesium-oxide doped lithium niobate (PPMgLN)-based optical parametric oscillator (OPO).
• Implemented a semi-external-cavity design to simplify the system and manage thermal effects.

Main Results:

• Achieved 4.75 W of MIR output at 3.81 µm.
• Obtained a pump to MIR conversion efficiency of 15.17% under 31.31 W pump power at 50 kHz repetition rate.
• Measured high beam quality with M² factors of 1.72 (horizontal) and 1.87 (vertical).

Conclusions:

• The developed compact fiber laser-pumped OPO system is effective for generating high-power MIR radiation.
• The semi-external-cavity design successfully mitigates thermal lensing, enabling high-power operation.
• The system offers a promising solution for applications requiring efficient, high-quality MIR sources.