Research On Properties Of Plasmons In Semiconducting Carbon Nanotubes

The surface plasmon is a kind of quasiparticles with the behavior of the bosons produced by the coupling of free electrons and electromagnetic waves.The surface plasmons have attracted wide attention due to their excellent properties of breakthrough diffraction limit propagation and localized electric field enhancement.As the carrier of the traditional surface plasmon,the noble metal is limited in its application,which can be attributed to its high loss,low confinement,and the untuned carrier.The one-dimensional nature of carbon nanotubes and the unique ballistic transport mode of the electrons make the carbon nanotubes plasmons strong spatial confinement and low loss.One of the characteristics of semiconducting carbon nanotubes is the tunability of carrier concentration.In this paper,the optical properties of surface plasmons in semiconducting carbon nanotubes are studied by Raman method and near-field optical imaging technology.Here,we use chemical doping to realize the real-space imaging of plasmons in semiconducting carbon nanotubes.The Raman method is used to judge the doping type and the underlying mechanism.Using mid-infrared near-field optical imaging technology,the plasmonic properties of semiconducting carbon nanotubes are systematically studied.The experimental results show that the hole is generated by nitric acid doping.On the one hand,the plasmonic oscillation in semiconducting carbon nanotubes is excited,and on the other hand,tuning of the optical properties of plasmons is achieved.In short,we achieve real-space imaging of plasmons in semiconducting carbon nanotubes at nanoscale resolution,and study the quality factor,spatial confinement,and dispersion behavior of plasmons.It is found that the plasmons in the nanotubes have excellent properties with low loss and strong spatial confinement.It brings new hopes for nanoscale photonic control and semiconducting integrated devices that have reached the size limit.