Angular Engineering Strategy for Enhanced Surface Nonlinear Frequency Conversion in Centrosymmetric Topological...

Area of Science:

• Materials Science
• Optics
• Condensed Matter Physics

Background:

• Surface nonlinear optics are crucial for advanced photonics and optoelectronics.
• Efficiency is limited by material susceptibility and interaction length.

Purpose of the Study:

• To demonstrate a centrosymmetric topological semimetal with enhanced surface nonlinear optical properties.
• To achieve efficient second-harmonic generation (SHG) through angular engineering.

Main Methods:

• Utilized an angular engineering strategy.
• Investigated the topological semimetal HfGe0.92Te crystal.

Main Results:

• Achieved a giant and anisotropic surface second-order nonlinear susceptibility (5535 ± 308 pm V⁻¹).
• Observed unprecedentedly efficient second-harmonic generation (SHG) with a maximum conversion efficiency of 3.75‰.
• Demonstrated maintained high efficiency across visible to deep-UV wavelengths due to linear dispersion near Dirac points.

Conclusions:

• HfGeTe crystals offer a promising platform for topological photonics.
• This work facilitates the development of integrated nonlinear photonics based on topological semimetals.