Resonantly Enhanced Second-Harmonic Generation Using III-V Semiconductor All-Dielectric Metasurfaces

Area of Science:

• Nonlinear optics
• Nanophotonics
• Materials science

Background:

• Nanostructured materials offer unique control over optical fields, enhancing nonlinear optical processes.
• Dielectric resonator metamaterials provide larger mode volumes than plasmonic structures for nonlinear applications.

Purpose of the Study:

• To demonstrate resonantly enhanced second-harmonic generation (SHG) in gallium arsenide (GaAs) dielectric metasurfaces.
• To investigate the potential of dielectric metasurfaces for efficient nonlinear frequency conversion.

Main Methods:

• Fabrication of GaAs-based dielectric metasurfaces with arrays of cylindrical resonators.
• Measurement of second-harmonic generation (SHG) enhancement factors.
• Characterization of nonlinear conversion efficiency and polarization properties.

Main Results:

• Observed SHG enhancement factors up to 10^4 compared to unpatterned GaAs.
• Achieved an absolute nonlinear conversion efficiency of ~2 × 10^-5 at magnetic dipole resonance with ~3.4 GW/cm^2 pump intensity.
• Identified contributions from both bulk and surface nonlinearities to the SHG process.

Conclusions:

• GaAs dielectric metasurfaces enable significant resonant enhancement of SHG.
• These metasurfaces offer a promising platform for efficient nonlinear optical frequency conversion.
• Understanding the interplay of bulk and surface nonlinearities is crucial for optimizing such devices.