Z-scan measurement of the nonlinear refractive index of graphene

Han Zhang, Stephane Virally, Qiaoliang Bao, Loh Kian Ping, Serge Massar, Nicolas Godbout, Pascal Kockaert

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Abstract

Under strong laser illumination, few-layer graphene exhibits both a transmittance increase due to saturable absorption and a nonlinear phase shift. Here, we unambiguously distinguish these two nonlinear optical effects and identify both real and imaginary parts of the complex nonlinear refractive index of graphene. We show that graphene possesses a giant nonlinear refractive index n2 ≃ 10−7 cm2 W−1, almost 9 orders of magnitude larger than bulk dielectrics. We find that the nonlinear refractive index decreases with increasing excitation flux but slower than the absorption. This suggests that graphene may be a very promising nonlinear medium, paving the way for graphene-based nonlinear photonics. © 2012 Optical Society of America
Original languageEnglish
Pages (from-to)1856-1858
Number of pages3
JournalOptics Letters
Volume37
Issue number11
DOIs
Publication statusPublished - 2012
Externally publishedYes

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