Broadly tunable mode-hop-free mid-infrared light source with MgO:PPLN continuous-wave optical parametric oscillator

Area of Science:

• Laser Physics
• Spectroscopy
• Nonlinear Optics

Background:

• Mid-infrared lasers are crucial for molecular spectroscopy.
• Broadly tunable and stable sources are needed for high-resolution measurements.
• MgO:PPLN (periodically poled lithium niobate doped with magnesium oxide) is a key nonlinear material for frequency conversion.

Purpose of the Study:

• To develop a continuous-wave, broadly tunable mid-infrared optical parametric oscillator (OPO).
• To achieve the broadest mode-hop-free (MHF) tuning range for mid-infrared idler light.
• To demonstrate the application of this tunable laser in high-resolution absorption spectroscopy.

Main Methods:

• Utilized a fiber amplifier as the pump source for the MgO:PPLN OPO.
• Employed synchronized pump tuning and temperature optimization for OPO operation.
• Performed high-resolution absorption spectroscopy of methane using the tunable mid-infrared laser.

Main Results:

• Achieved a broadly tunable, continuous-wave mid-infrared output from the MgO:PPLN OPO.
• Demonstrated the broadest mode-hop-free (MHF) tuning range of idler light, exceeding 30 cm(-1).
• Successfully applied the tunable laser to high-resolution absorption spectroscopy of methane.

Conclusions:

• The developed MgO:PPLN OPO provides a stable and broadly tunable mid-infrared source.
• The achieved MHF tuning range is unprecedented for this type of laser system.
• This laser system is well-suited for high-resolution molecular spectroscopy applications.