Chirality-Dependent Second Harmonic Generation of MoS₂ Nanoscroll with Enhanced Efficiency

Area of Science:

• Materials Science
• Nanotechnology
• Optics

Background:

• High second harmonic generation (SHG) efficiency and reduced dimensions are crucial for integrated photonics and nonlinear optical applications.
• Two-dimensional (2D) materials offer unique properties but their application in nanostructures requires further investigation.

Purpose of the Study:

• To fabricate molybdenum disulfide (MoS2) nanoscrolls with varying chiralities.
• To investigate the second harmonic generation (SHG) performance of these MoS2 nanoscrolls.
• To explore the potential of MoS2 nanoscrolls in nonlinear optics and integrated photonics.

Main Methods:

• Fabrication of MoS2 nanoscrolls with controlled chiralities.
• Polarization-resolved second harmonic generation (SHG) characterization.
• Theoretical analysis based on the superposition theory of second harmonic fields.

Main Results:

• MoS2 nanoscrolls exhibit reduced symmetry and strong chirality-dependent SHG.
• SHG intensity of certain MoS2 nanoscrolls was up to 95 times higher than that of monolayer MoS2.
• SHG performance is well explained by the superposition theory of nanoscroll walls' second harmonic fields.

Conclusions:

• MoS2 nanoscrolls are promising candidates for enhanced nonlinear optical applications due to their chirality-dependent SHG.
• The findings are applicable to other non-centrosymmetric 2D materials like WS2, WSe2, and hBN.
• The study presents a nondestructive method for determining nanoscroll/nanotube chiralities.