Enhancement of Optical Nonlinearity in the Triangular Gold Nanoplates on Indium Tin Oxide

The nonlinear optical materials with small footprint, low operating energy, ultrafast and large nonlinear optical response are highly required for the signal processing. Here, we investigated the broadband optical nonlinear response of the triangular gold nanoplates on indium tin oxide (ITO) coated glass, and obtained a large optical nonlinear enhancement at its localized surface plasmon resonance (LSPR) region at the wavelength of 780 nm, far from the ENZ (epsilon-near-zero) region of ITO. The measured nonlinear refractive index and nonlinear absorption coefficient can reach up to 8.39×10 -15 m 2 /W and 5.81×10 -8 m/W, respectively. The experimental results highlight the noble metals' potential for nonlinear optics and nanophotonics.