Observation of large nonlinear responses in a graphene-Bi2Te3 heterostructure at a telecommunication wavelength

Yingwei Wang, Haoran Mu, Xiaohong Li, Jian Yuan, Jiazhang Chen, Si Xiao, Qiaoliang Bao, Yongli Gao, Jun He

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We report the large nonlinear response and ultrafast carrier relaxation dynamics of a graphene-Bi2Te3 heterostructure produced by two-step chemical vapour deposition. The nonlinear refractive index reaches n2 = 0.2 × 10-7 cm2/W at the telecommunication wavelength of 1550 nm, which is almost seven orders of magnitude larger than that of the bulk Si material. Additionally, a pump-probe experiment is performed to investigate the ultrafast dynamic process (intraband relaxation time τ1 = 270 ± 20 fs; interband relaxation time τ2 = 3.6 ± 0.2 ps) of the graphene-Bi2Te3 heterostructure. Then, based on the donor-acceptor structure model, we propose a theoretical model to explain the dynamic relaxation process. Our results show that the graphene-Bi2Te3 heterostructure is a promising saturable absorber for ultrafast pulse laser applications at telecommunication wavelengths.

Original languageEnglish
Article number221901
Number of pages5
JournalApplied Physics Letters
Issue number22
Publication statusPublished - 30 May 2016
Externally publishedYes

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