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

Jing Huang,Lili Miao,Dongyang Liu,Jie Li,Chujun Zhao

doi:10.1109/jphot.2021.3085871

Abstract

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.

Highlights

Optical materials with large nonlinear optical response are highly required for the signal processing
The gold nanoparticles were dispersed in an aqueous solution with optical density (OD) equal to 1, and the single piece of gold triangular is an equilateral triangular with side length (L) is 140 ± 25 nm, and the thickness is 8 ± 2 nm
By translating the sample along the optical axis of the focused laser beam, the sample will be exposed to different light intensities, and we measured the transmittance of the sample under different light to study its nonlinear optical response

Summary

Introduction

Optical materials with large nonlinear optical response are highly required for the signal processing. Metamaterials have been predicted to enable a plethora of novel light-matter interactions [16], exhibiting an interplay of electric and magnetic-type nonlinearities [17], [18] In another case, plasmonic nanostructures provide inside and interior local field enhancement and, as a result, nonlinear effects can be obvious, including the generation of new frequencies and ultrafast, transient variations of the fundamental wave’s intensity [19]–[23]. Metallic nanoparticles deposited on transparent substrates exhibit structure and geometry-dependent optical properties due to the occurrence of local surface plasmon resonance (LSPR) effects. We have experimentally investigated the broadband third-order optical nonlinear response of the triangular gold nanoplates onto ITO glass, and the results show a large optical nonlinear enhancement at nanoplates’ LSPR region. Our results show the potential applications of the nanostructure in the nonlinear optics and optoelectronic devices

Materials Characterizations

Experimental Results and Discussions

Conclusion