2018/08/12 by Yu Song, Song, Yu, Siqi Hu +8 · 2 citations
Materials Science · Physics and Astronomy · #2D Materials and Applications #Advanced Fiber Laser Technologies #Applied Physics (physics.app-ph) #FOS: Physical sciences #Laser-Matter Interactions and Applications #Optics (physics.optics)
paper · pdf · doi:10.48550/arxiv.1808.03928
openalex publication_date 2018/08/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report the observations of unexpected layer-dependent, strong, and anisotropic second harmonic generations (SHGs) in atomically thin ReS2. Appreciable (negligible) SHGs are obtained from even (odd) numbers of ReS2 layers, which is opposite to the layer-dependence of SHGs in group VI transition metal dichalcogenides, such as MoS2 and WS2. The results are analyzed from ReS2's crystal structure, implying second harmonic polarizations generated from the interlayer coupling. Pumped by a telecomband laser, SHG from the bilayer ReS2 is almost one order of magnitude larger than that from the monolayer WS2. The estimated second-order nonlinear susceptibility of 900 pm/V is remarkably high among those reported in two-dimensional materials. The laser polarization dependence of ReS2's SHG is strongly anisotropic and indicates its distorted lattice structure with more unequal and non-zero second-order susceptibility elements.