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Thermal Nonlinearity of Functionalized Graphene Enhanced by Gold Nanorods




Author(s)

Thekrayat Al Abdulaal and Gregory Salamo

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DOI:10.17265/2328-2223/2017.04.001

The nonlinearity of functionalized and nonfunctionlaized graphene as well as gold nanorods were investigated using the Z-scan system with an Ar⁺ laser beam tuned at a wavelength of 514 nm in a CW (continuous wave) regime that was in resonance with AuNRs (gold nanorods). Z-scan experimental study indicated that functionalized graphene had a negative nonlinear refraction with self-defocusing performance. The result concluded that gold nanorods (average length was 36 ± 3 nm, and the average diameter was 12 ± 2 nm) enhance the thermal nonlinear properties of graphene oxide materials. Gold nanorods were proved to enhance the nonlinear absorption by 50%, and there was a large enhancement on the thermal nonlinear refraction and the thermo-optical coefficient (dn/dT). It was observed that the AuFG (functionalized graphene film with gold nanorods) presented a large thermal nonlinear refraction. The value of the nonlinear refraction (n₁^’) of FG and AuFG samples was shifted from -0.533 × 10^-7 cm²/W to -2.92 × 10^-7 cm²/W. There was a large enhancement in thermal refraction value that was about five factors larger than the nonlinear refraction of the host material (FG) and much larger (4 orders of magnitude) than that for AuNRs.

Functionalized graphene, gold nanorods, nonlinear absorption, refractive index, thermal nonlinearity.