Multigrating quasi-phase-matched optical parametric oscillator in periodically poled LiNbO(3)

Area of Science:

• Optics and Photonics
• Nonlinear Optics
• Laser Physics

Background:

• Optical parametric oscillators (OPOs) are crucial for generating tunable laser light.
• Quasi-phase-matching (QPM) in nonlinear crystals like lithium niobate (LiNbO3) enables efficient frequency conversion.
• Developing widely tunable and efficient OPOs is essential for various spectroscopic and photonic applications.

Purpose of the Study:

• To demonstrate a widely tunable quasi-phase-matched optical parametric oscillator (QPM OPO).
• To utilize a multigrating periodically poled LiNbO3 crystal for broad tunability.
• To achieve efficient infrared output with minimal operational complexity.

Main Methods:

• Employed a multigrating periodically poled LiNbO3 crystal within an optical resonator.
• Tuned the OPO by translating the crystal through the resonator and pump beam, eliminating realignment.
• Used a 1.064-micrometer acousto-optically Q-switched Nd:YAG laser as the pump source.

Main Results:

• Achieved noncritically phase-matched tunable infrared (IR) output spanning from 1.36 to 4.83 micrometers.
• Observed a low threshold of 6 microJoules for a 26-mm interaction length.
• Demonstrated superior IR transmission for the extraordinary polarization of LiNbO3, enabling longer wavelength operation via d(33) QPM.

Conclusions:

• The developed QPM OPO offers wide tunability and efficient IR generation.
• The multigrating PPLN design and translation tuning method provide a robust and realignment-free system.
• The enhanced IR transmission of extraordinary polarized LiNbO3 facilitates longer wavelength generation compared to conventional methods.