Photonics Research, 2019, 7 (7): 07000762, Published Online: Jun. 21, 2019
Layer-modulated two-photon absorption in MoS2: probing the shift of the excitonic dark state and band-edge Download: 788次
Abstract
Questions hovering over the modulation of bandgap size and excitonic effect on nonlinear absorption in two-dimensional transition metal dichalcogenides (TMDCs) have restricted their application in micro/nano optical modulator, optical switching, and beam shaping devices. Here, degenerate two-photon absorption (TPA) in the near-infrared region was studied experimentally in mechanically exfoliated from single layer to multilayer. The layer-dependent TPA coefficients were significantly modulated by the detuning of the excitonic dark state ( ). The shift of the quasiparticle bandgap and the decreasing of exciton binding energy with layers were deduced, combined with the non-hydrogen model of excitons in TMDCs and the scaling rule of semiconductors. Our work clearly demonstrates the layer modulation of nonlinear absorption in TMDCs and provides support for layer-dependent nonlinear optical devices, such as optical limiters and optical switches.
Yafeng Xie, Saifeng Zhang, Yuanxin Li, Ningning Dong, Xiaoyan Zhang, Lei Wang, Weimin Liu, Ivan M. Kislyakov, Jean-Michel Nunzi, Hongji Qi, Long Zhang, Jun Wang. Layer-modulated two-photon absorption in MoS2: probing the shift of the excitonic dark state and band-edge[J]. Photonics Research, 2019, 7(7): 07000762.