Year: 2026
Type: article
Abstract: Van der Waals stacking presents new opportunities for nonlinear optics with its remarkable tunability and scalability. However, the fundamental role of interlayer interactions in modifying the overall nonlinear optical susceptibilities remains elusive. In this paper, we report anisotropic enhancement of second-harmonic generation (SHG) from a WS2/ReSe2 heterobilayer, where the individual composite layers possess distinctive crystal phases. We investigate polarization-resolved response and twist-angle dependence in SHG and reveal that band alignment alone is insufficient to explain the observed anisotropy in the modified SHG response. Spectral shifts in excitonic features highlight band renormalization, supporting the role of hybridization between the two layers. Furthermore, SHG enhancement is highly anisotropic and can even be suppressed in some orientations, suggesting possible intensity-borrowing mechanisms within the heterostructure. Our work demonstrates the ability to tune both the intensity and polarization dependence of nonlinear optical responses with van der Waals stacking of distinctive crystal phases.
Source: The Journal of Chemical Physics
Authors: Kanchan Shaikh, Taejun Yoo, Zeyuan Zhu, Qiuyang Li, Amalya C. Johnson, Hui Deng, Fang Liu, Yuki Kobayashi
Institutions: University of Michigan, Stanford University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4417414036