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Proceedings Paper

Second-harmonic generation in an atomic phase-matched nonlinear 2D crystal (Presentation Recording)
Author(s): Mervin Zhao; Ziliang Ye; Yu Ye; Hanyu Zhu; Yuan Wang; Yoshihiro Iwasa; Xiang Zhang

Paper Abstract

The second harmonic generation (SHG) produced from two-dimensional atomic crystals have been utilized recently in studying the grain boundaries and electronic structure of such ultra-thin materials. However, the SHG in many of these crystals, such as transition metal dichalcogenides (TMDCs), only occur in odd numbered layers with limited intensity due to their noncentrosymmetric nature. Here, we probe the SHG from the bulk noncentrosymmetric molybdenum disulfide (MoS2). Whereas the commonly studied 2H crystal phase’s anti-parallel nonlinear dipoles in adjacent layers give an oscillatory SH response, the parallel nonlinear dipoles of each atomic layer in the 3R phase constructively interfere to amplify the nonlinear light. Due to this interference, we observed the atomically phase-matched condition yielding a quadratic dependence between the intensity and layer number. Additionally, we probed the layer evolution of the A and B excitonic transitions in 3R-MoS2 using SHG spectroscopy and found distinct electronic structure differences arising from the crystal geometry. These findings demonstrate the dramatic effect of the symmetry and layer stacking of these atomic crystals.

Paper Details

Date Published: 5 October 2015
PDF: 1 pages
Proc. SPIE 9552, Carbon Nanotubes, Graphene, and Emerging 2D Materials for Electronic and Photonic Devices VIII, 95520H (5 October 2015); doi: 10.1117/12.2187575
Show Author Affiliations
Mervin Zhao, Univ. of California, Berkeley (United States)
Ziliang Ye, Univ. of California, Berkeley (United States)
Yu Ye, Univ. of California, Berkeley (United States)
Hanyu Zhu, Univ. of California, Berkeley (United States)
Yuan Wang, Univ. of California, Berkeley (United States)
Yoshihiro Iwasa, The Univ. of Tokyo (Japan)
Xiang Zhang, Univ. of California, Berkeley (United States)


Published in SPIE Proceedings Vol. 9552:
Carbon Nanotubes, Graphene, and Emerging 2D Materials for Electronic and Photonic Devices VIII
Manijeh Razeghi; Maziar Ghazinejad; Can Bayram; Jae Su Yu; Young Hee Lee, Editor(s)

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