Ultrafast coherent nonlinear nanooptics and nanoimaging of graphene

Tao Jiang, Vasily Kravtsov, Mikhail Tokman, Alexey Belyanin, Markus B. Raschke

פרסום מחקרי: פרסום בכתב עתמאמרביקורת עמיתים

96 ציטוטים ‏(Scopus)

תקציר

With its linear energy dispersion and large transition dipole matrix element, graphene is an attractive material for nonlinear optoelectronic applications. However, the mechanistic origin of its strong nonlinear response, the ultrafast coherent dynamics and the associated nanoscale phenomena have remained elusive due to a lack of suitable experimental techniques. Here, using adiabatic nanofocusing and imaging, we study the broadband four-wave mixing (FWM) response of graphene with nanometre and femtosecond spatio-temporal resolution. We detect a nonlinear signal enhancement at the edges and dependence on the number of layers from excitation areas as small as 104 carbon atoms. Femtosecond FWM nanoimaging and concomitant frequency-domain measurements reveal dephasing on T2 ≈ 6 ± 1 fs timescales, which we attribute to a strong electron–electron interaction. We also identify an unusual non-local FWM response on ~100–400 nm length scales, which we assign to a Doppler effect controlling the nonlinear interaction between the tip near-field momenta and the graphene electrons with high Fermi velocity. These results illustrate the distinct nonlinear nanooptical properties of graphene, expected also in related classes of two-dimensional materials, that could form the basis for improved nonlinear and ultrafast nanophotonic devices.

שפה מקוריתאנגלית
עמודים (מ-עד)838-843
מספר עמודים6
כתב עתNature Nanotechnology
כרך14
מספר גיליון9
מזהי עצם דיגיטלי (DOIs)
סטטוס פרסוםפורסם - 1 ספט׳ 2019
פורסם באופן חיצוניכן

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