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Second Harmonic Generation in Atomically Thin MoTe 2
Author(s) -
Song Yu,
Tian Ruijuan,
Yang Jiulong,
Yin Rui,
Zhao Jianlin,
Gan Xuetao
Publication year - 2018
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201701334
Subject(s) - monolayer , second harmonic generation , point reflection , materials science , second harmonic imaging microscopy , thin film , surface second harmonic generation , polarization (electrochemistry) , phase transition , order (exchange) , laser , nonlinear optical , condensed matter physics , optoelectronics , optics , nonlinear system , nanotechnology , physics , chemistry , finance , quantum mechanics , economics
Optical second harmonic generations (SHGs) from atomically thin MoTe 2 flakes with 2H and 1T′ phases are studied. From 2H‐MoTe 2 samples with odd (even) numbers of layers, strong (negligible) SHGs are observed due to the layer‐dependent broken inversion symmetry. When pumped by a telecom‐band laser, SHG from a monolayer 2H‐MoTe 2 is about one order of magnitude stronger than that from a monolayer WS 2 ; an extremely high second‐order nonlinear susceptibility of 2.5 nm V −1 is estimated, presenting the highest value among those reported in 2D materials. SHG measurements in MoTe 2 are also demonstrated as an efficient way to distinguish the 2H‐to‐1T′ phase transition. Compared with the SHG in 2H‐MoTe 2 , 1T′‐MoTe 2 's SHG has much lower efficiency and the polarization dependence is changed from a six‐fold pattern to a two‐lobe pattern.