3- W, 3.8 µm self-optical parametric oscillator by pulsed pumping based on Nd:MgO:PPLN crystal

Area of Science:

• Optics and Photonics
• Laser Physics
• Nonlinear Optics

Background:

• Mid-infrared light generation is crucial for various applications, including spectroscopy and sensing.
• Self-optical parametric oscillators (SOPOs) offer a compact approach to generating mid-infrared radiation.
• Heat accumulation in nonlinear crystals under high-power laser pumping is a significant challenge.

Purpose of the Study:

• To develop a compact and efficient 3.8 µm self-optical parametric oscillator (SOPO).
• To optimize heat management in the nonlinear crystal for improved performance.
• To achieve high output power and stable operation in the mid-infrared region.

Main Methods:

• Utilized a single Nd:MgO:PPLN crystal for both fundamental light generation and parametric down-conversion.
• Employed a pulsed laser diode (LD) as the pump source.
• Optimized crystal properties and pumping conditions to suppress non-matching polarized fundamental light and satisfy polarization matching.

Main Results:

• Achieved a stable π-polarized 1084 nm fundamental light output across the entire pumping range.
• Demonstrated a maximum output power of 3.04 W at 3814 nm in pulse pumping mode.
• Obtained a repetition frequency of 25.11 kHz and a single pulse width of 11.45 ns, representing the highest output power for 3.8 µm SOPOs.

Conclusions:

• The developed SOPO system is compact, stable, and highly efficient.
• The optimized method effectively mitigates heat accumulation issues in the Nd:MgO:PPLN crystal.
• This work sets a new benchmark for output power in 3.8 µm SOPOs, paving the way for advanced mid-infrared applications.