2013/02/28 by Nardeep Kumar, Sina Najmaei, Qiannan Cui +4 · 1 citation
Physics and Astronomy · #cond-mat.mes-hall #cond-mat.mtrl-sci #physics.optics
paper · pdf · doi:10.1103/physrevb.87.161403
published as Phys. Rev. B 87, 161403(R) (2013) · 6 pages, 4 figures
arxiv created 2013/04/06 · arxiv updated 2015/06/15
We show that the lack of inversion symmetry in monolayer MoS2 allows strong optical second harmonic generation. Second harmonic of an 810-nm pulse is generated in a mechanically exfoliated monolayer, with a nonlinear susceptibility on the order of 1E-7 m/V. The susceptibility reduces by a factor of seven in trilayers, and by about two orders of magnitude in even layers. A proof-of-principle second harmonic microscopy measurement is performed on samples grown by chemical vapor deposition, which illustrates potential applications of this effect in fast and non-invasive detection of crystalline orientation, thickness uniformity, layer stacking, and single-crystal domain size of atomically thin films of MoS2 and similar materials.