Observation of Anisotropic Second Harmonic Generation in Two-Dimensional Niobium Diselenide

• DOI: 10.1021/acs.jpclett.4c00923
• Publication Date: 2024-05-02T12:30:20Z
• Authors: Khansa Younus; Yu Zhou; Menglong Zhu; Defeng Xu; Xiao Guo; Asad Ahmed; Fangping Ouyang; Han Huang; Si Xiao; Zhihui Chen; Jun He
• Keywords: Second-harmonic imaging microscopy; Diselenide; Crystal (programming language); Nanometre

The intrinsic anisotropy of NbSe2 provides a favorable prerequisite second harmonic generation (SHG) and rich possibilities for tailoring its nonlinear optical (NLO) properties. Here we report the highly efficient SHG mechanically exfoliated flakes. response changes with excitation wavelengths, layer thicknesses, polarizations laser. anisotropic further exhibits non-centrosymmetric crystal structure could effectively assign crystalline orientation Interestingly, although flakes tens nanometers thickness experience attenuations in performance, more ratios were obtained, which are around 4 times higher than that 5-layer counterpart. determined second-order nonlinearities (monolayer: ∼1.0 × 103 pm/V; 3-layer: ∼73 pm/V) comparable to those commonly reported two-dimensional materials (e.g., MoS2, WSe2, graphene) same number layers much commercial crystals.