42%-efficient single-pass cw second-harmonic generation in periodically poled lithium niobate

Area of Science:

• Photonics and Nonlinear Optics
• Materials Science and Engineering
• Solid-State Physics

Background:

• Periodically poled lithium niobate (PPLN) is crucial for nonlinear optical frequency conversion.
• Efficient fabrication of large-area PPLN with precise domain structures remains a challenge.
• Nd:YAG lasers require effective second-harmonic generation (SHG) for green light output.

Purpose of the Study:

• To present a novel full-wafer fabrication process for PPLN with a 6.5-micrometer domain period.
• To demonstrate the efficacy of the fabricated PPLN for continuous-wave (cw) second-harmonic generation.
• To characterize the nonlinear optical performance and conversion efficiency of the PPLN samples.

Main Methods:

• Developed a full-wafer fabrication technique for PPLN.
• Fabricated PPLN samples with dimensions of 53 mm length and 0.5 mm thickness.
• Utilized single-pass cw 1064-nm Nd:YAG laser for second-harmonic generation experiments.

Main Results:

• Achieved PPLN samples with 78% of the ideal nonlinear coefficient.
• Measured a low-power conversion efficiency of 8.5%/W for SHG.
• Demonstrated 42% power conversion efficiency, producing 2.7 W of 532-nm green light from 6.5 W of 1064-nm input.

Conclusions:

• The developed full-wafer fabrication process enables efficient production of PPLN for high-power nonlinear optical applications.
• The fabricated PPLN exhibits excellent performance for cw second-harmonic generation of Nd:YAG lasers.
• This advancement facilitates the generation of visible laser light with high efficiency and power.