Enhanced second harmonic generation from a quasi-periodic silver dendritic metasurface

Area of Science:

• Metasurfaces
• Nonlinear Optics
• Nanophotonics

Background:

• Current nonlinear optical metasurface fabrication relies on expensive, large-area-limited top-down methods like electron beam etching.
• Developing cost-effective and scalable methods for preparing high-performance metasurfaces is crucial for practical applications.

Purpose of the Study:

• To establish an easily prepared quasi-periodic silver dendritic metasurface model with a high quality factor (Q factor) in the near-infrared band.
• To investigate the second harmonic generation (SHG) properties of this metasurface, particularly its dependence on incident angle and structural parameters.

Main Methods:

• Utilized a simple and easy-to-operate electrochemical deposition method for metasurface fabrication.
• Employed simulations to analyze the Q factor, electric field localization, and SHG efficiency.
• Investigated the influence of incident angle and dendritic structure dimensions on performance.

Main Results:

• The silver dendritic metasurface achieved a high Q factor exceeding 10^4 due to strong electric field localization, similar to superposed split-ring resonators.
• Demonstrated a significant enhancement (approximately 30 times) in SHG intensity at a large incident angle (85°) compared to small angles when using x-polarized light.
• Simulations explored the impact of incident angle and structural dimensions on Q factor and SHG efficiency.

Conclusions:

• The electrochemical deposition method offers a scalable and cost-effective approach for preparing quasi-periodic silver dendritic metasurfaces.
• The demonstrated high Q factor and enhanced SHG efficiency make these metasurfaces promising for miniature, integratable nonlinear optical devices.
• This work provides a new pathway for developing advanced nonlinear optical devices for various applications.