We report the modulation of epsilon-near-zero(ENZ)wavelength and enhanced third-order nonlinearity in indium tin oxide(ITO)/Au multilayer films.The samples consisting of five-layer 40 nm ITO films spaced by four-layer...We report the modulation of epsilon-near-zero(ENZ)wavelength and enhanced third-order nonlinearity in indium tin oxide(ITO)/Au multilayer films.The samples consisting of five-layer 40 nm ITO films spaced by four-layer ultrathin Au films of different thickness,i.e.,ITO(40 nm)/[Au(x)/ITO(40 nm)]4,were prepared by magnetron sputtering at room temperature.The ENZ wavelength in the multilayer films is theoretically calculated and experimentally confirmed.The nonlinear refractive index and nonlinear absorption coefficient of the samples of x=0,2,3,4 nm were determined using the Z-scan method at a wavelength of 1.064μm.The large nonlinear refractive index n2=1.12×10^(−13) m^(2)=W and nonlinear absorption coefficient β=−1.78×10^(−7) m=W in the sample of x=4 nm are both four times larger than those in the single-layer ITO film.The large optical nonlinearity due to the ENZ enhancement and carrier concentration is discussed.The results indicate that the ITO/Au multilayer films are promising for advanced all-optical devices.展开更多
基金supported by the National Natural Science Foundation of China(No.12174228)Natural Science Foundation of Shandong Province(No.ZR2019MA024).
文摘We report the modulation of epsilon-near-zero(ENZ)wavelength and enhanced third-order nonlinearity in indium tin oxide(ITO)/Au multilayer films.The samples consisting of five-layer 40 nm ITO films spaced by four-layer ultrathin Au films of different thickness,i.e.,ITO(40 nm)/[Au(x)/ITO(40 nm)]4,were prepared by magnetron sputtering at room temperature.The ENZ wavelength in the multilayer films is theoretically calculated and experimentally confirmed.The nonlinear refractive index and nonlinear absorption coefficient of the samples of x=0,2,3,4 nm were determined using the Z-scan method at a wavelength of 1.064μm.The large nonlinear refractive index n2=1.12×10^(−13) m^(2)=W and nonlinear absorption coefficient β=−1.78×10^(−7) m=W in the sample of x=4 nm are both four times larger than those in the single-layer ITO film.The large optical nonlinearity due to the ENZ enhancement and carrier concentration is discussed.The results indicate that the ITO/Au multilayer films are promising for advanced all-optical devices.
