High-power, continuous-wave, mid-infrared optical parametric oscillator based on MgO:sPPLT

Area of Science:

• Nonlinear Optics
• Laser Physics
• Materials Science

Background:

• Continuous-wave (cw) mid-infrared (mid-IR) light sources are crucial for various applications, including spectroscopy and free-space communications.
• Developing high-power, stable, and tunable mid-IR sources remains a significant challenge in laser technology.

Purpose of the Study:

• To demonstrate a stable, high-power, cw mid-IR optical parametric oscillator (OPO).
• To investigate the performance of MgO-doped stoichiometric periodically poled lithium tantalate (MgO:sPPLT) as a gain medium for mid-IR generation.
• To assess the tunability, power, stability, and thermal characteristics of the MgO:sPPLT-based OPO.

Main Methods:

• Utilized a MgO:sPPLT crystal in a singly resonant oscillator (SRO) configuration.
• Pumped the OPO using a Yb fiber laser operating at 1064 nm.
• Tuned the output wavelength by adjusting the crystal temperature and poling period.

Main Results:

• Achieved a tunable output from 3032 to 3462 nm (430 nm tuning range).
• Generated a maximum mid-IR output power of 5.5 W, with over 4 W across 60% of the tuning range.
• Demonstrated room temperature operation with reduced thermal effects.
• Observed excellent idler power stability (<12.8% peak-to-peak over 5 h) and frequency stability (~1 GHz).

Conclusions:

• MgO:sPPLT is a highly effective material for generating multiwatt mid-IR radiation.
• The developed OPO offers stable, tunable, and high-power mid-IR output suitable for demanding applications.
• The material's performance confirms its potential for advanced laser systems operating near room temperature.