Continuous-wave total-internal-reflection optical parametric oscillator pumped at 1064 nm

Area of Science:

• Laser Physics and Photonics
• Nonlinear Optics
• Materials Science (Lithium Niobate)

Background:

• Optical Parametric Oscillators (OPOs) are crucial for generating tunable laser light.
• Previous OPO designs faced limitations in efficiency, stability, and tunability.
• Development of compact, stable, and efficient OPOs is an ongoing research area.

Purpose of the Study:

• To report the first continuous-wave (cw) 1064-nm-pumped optical parametric oscillator (OPO).
• To demonstrate a monolithic, doubly resonant OPO utilizing total-internal-reflection.
• To investigate the performance characteristics, including threshold, stability, and tunability.

Main Methods:

• Fabrication of a monolithic, doubly resonant OPO from congruent lithium niobate (LiNbO3).
• Utilizing critically phase-matched (θpm = 45.5°) configuration.
• Employing frustrated total-internal-reflection for variable output coupling of signal and idler waves.

Main Results:

• Achieved a measured finesse of 6000 at 2014 nm, indicating a low round-trip power loss of 0.1%.
• Demonstrated a low threshold power of 130 mW, compensating for Poynting vector walk-off.
• Observed stable, single axial-mode pair oscillation for over 30 minutes due to passive thermal feedback.
• Tuned the OPO output from 2040 to 2225 nm in 0.1-nm steps by adjusting pump frequency.

Conclusions:

• The developed monolithic, total-internal-reflection, doubly resonant OPO represents a significant advancement in OPO technology.
• The device exhibits excellent performance metrics, including low threshold, high finesse, and stable single-mode operation.
• The demonstrated tunability and stability open possibilities for various spectroscopic and photonic applications.