In-plane anisotropic third-harmonic generation from germanium arsenide thin flakes

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) layered germanium arsenide (GeAs) exhibits significant in-plane anisotropy.
• GeAs shows potential for photonic and optoelectronic applications, including photodetection and electronics.
• The nonlinear optical properties of 2D GeAs remain largely unexplored.

Purpose of the Study:

• To investigate the intrinsic nonlinear optical properties of 2D layered GeAs.
• To explore thickness- and polarization-dependent third-harmonic generation (THG) in GeAs.
• To determine optimal GeAs flake thickness for high THG conversion efficiency.

Main Methods:

• Mechanically exfoliated thin GeAs flakes were used for experiments.
• Thickness- and incident polarization-dependent THG measurements were performed.
• Stokes parameters were analyzed to characterize the polarization of the emitted THG signal.

Main Results:

• Anisotropic third-harmonic generation (THG) was observed in 2D GeAs flakes.
• The THG conversion efficiency was found to be dependent on flake thickness and incident polarization.
• Optimal thickness ranges for high THG efficiency were identified.
• Control over the intensity and polarization of TH emission was demonstrated.

Conclusions:

• This study reveals the intrinsic nonlinear optical properties of 2D GeAs.
• The findings highlight GeAs as a promising material for anisotropic optical devices.
• Results pave the way for advancements in photonic integration, optical communication, and information processing.