Study on optical limiting effect of graphene in midinfrared band
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Graphical Abstract
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Abstract
The optical limiting effect of the graphene films in midinfrared band (3 m~5 m) was studied using nanosecond pulsed laser Zscan method . The Zscan curve obtained from the open aperture experiment showed a single valley structure, but the same structure did not show in the closedaperture Zscan curve. Through the fitting and calculation of the openaperture Zscan curve, the 3order nonlinear absorption coefficients and the optical limiting thresholds of 3 layers graphene were 11.3910-7cm/W, 10.6110-7cm/W, 9.7510-7cm/W, 8.8110-7 cm/W and 3.49 J/cm2, 3.75 J/cm2, 4.11 J/cm2, 4.55 J/cm2 at 3.010 m, 3.522 m, 4.326 m and 4.880 4 m, respectively. The 3order nonlinear absorption coefficients and the optical limiting thresholds of 3 layers, 5 layers and 7 layers graphene in 3.522 m center wavelength were 10.6110-7cm/W, 11.3210-7cm/W, 11.9510-7cm/W and 3.75 J/cm2,3.41 J/cm2,3.32 J/cm2, respectively. The experimental results show the optical limiting effect of graphene is obvious in the midinfrared band based on nonlinear reverse saturable absorption.
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