Quasi-phase-matched frequency doubling in bulk periodic polymeric structures

Area of Science:

• Materials Science
• Nonlinear Optics
• Polymer Science

Background:

• Freestanding poled polymer films are crucial for nonlinear optical applications.
• Fabricating such films with low loss and high efficiency presents challenges.
• Existing methods may lack scalability or precise control over film properties.

Purpose of the Study:

• To introduce a novel fabrication technique for freestanding poled polymer films.
• To demonstrate the application of these films in bulk periodic synthetic-crystal structures.
• To achieve efficient quasi-phase-matching for second-harmonic generation.

Main Methods:

• Utilized a metallic film as a sacrificial lifting-off layer during polymer film fabrication.
• Fabricated bulk periodic synthetic-crystal structures with low transmission loss.
• Investigated structures satisfying quasi-phase-matching conditions for nonlinear frequency conversion.

Main Results:

• Achieved a second-harmonic generation efficiency of approximately 10(-2)% for a 150 micrometer thick film.
• Demonstrated the feasibility of producing low-transmission-loss periodic structures.
• Established the effectiveness of the metallic lifting-off layer technique.

Conclusions:

• The reported fabrication technique offers a viable route to high-quality freestanding poled polymer films.
• The developed synthetic-crystal structures show promise for efficient nonlinear optical applications.
• Further optimization of phase-matching angles can enhance second-harmonic conversion efficiency.