Atomically phase-matched second-harmonic generation in a 2D crystal.

ABSTRACT: Second-harmonic generation (SHG) has found extensive applications from hand-held laser pointers to spectroscopic and microscopic techniques. Recently, some cleavable van der Waals (vdW) crystals have shown SHG arising from a single atomic layer, where the SH light elucidated important information such as the grain boundaries and electronic structure in these ultra-thin materials. However, despite the inversion asymmetry of the single layer, the typical crystal stacking restores inversion symmetry for even numbers of layers leading to an oscillatory SH response, drastically reducing the applicability of vdW crystals such as molybdenum disulfide (MoS₂). Here, we probe the SHG generated from the noncentrosymmetric 3R crystal phase of MoS₂. We experimentally observed quad

SUBMITTER: Zhao M 

PROVIDER: S-EPMC6059936 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature