Optimization of nanocavity field enhancement using two-dimensional plasmonic photonic crystals  

作　　者：TAO Xing DONG ZhenChao 

机构地区：[1]Hefei National Laboratory for Physical Sciences at the Microscale,University of Science and Technology of China,Hefei 230026,China

出　　处：《Chinese Science Bulletin》2012年第1期77-82,共6页

基　　金：supported by the National Basic Research Program of China(2006CB922003,2011CB921402);Chinese Academy of Sciences(KJCX2.YW.H06);National Natural Science Foundation of China(91021004,10574117,10974186)

摘　　要：We have investigated the influence of Ag nanorod radius(r)on the resonant modes of a two-dimensional plasmonic photonic crystal(PPC)with dipole sources embedded into the central vacancy area,using finite-difference time-domain methods.Both the localized surface plasmon(LSP)mode of individual Ag nanorods and the resonant cavity mode of PPC are found to vary as a function of r.The resonant cavity mode is strongly enhanced as r is increased,while the LSP signal will eventually become no longer discernable in the Fourier spectrum of the time-evolved field.An optimized condition for the nanocavity field enhancement is found for a given PPC periodicity(e.g.d=375 nm)with the critical nanorod radius rc=d/3.At this point the resonant cavity mode has the strongest field enhancement,best field confinement and largest Q-factor.We attribute this to competition between the blocking of cavity confined light to radiate out when the cavity resonant frequency falls inside the opened photonic stopband as r reaches rc,and the transfer of cavity mode energy to inter-particle plasmons when r is further increased.We have investigated the influence of Ag nanorod radius （r） on the resonant modes of a two-dimensional plasmonic photonic crystal （PPC） with dipole sources embedded into the central vacancy area, using finite-difference time-domain methods. Both the localized surface plasmon （LSP） mode of individual Ag nanorods and the resonant cavity mode of PPC are found to vary as a function of r. The resonant cavity mode is strongly enhanced as r is increased, while the LSP signal will eventually become no longer discemable in the Fourier spectrum of the time-evolved field. An optimized condition for the nanocavity field enhancement is found for a given PPC periodicity （e.g. d= 375 nm） with the critical nanorod radius rc = d/3. At this point the resonant cavity mode has the strongest field enhancement, best field confinement and largest Q-factor. We attribute this to competition between the blocking of cavity confined light to radiate out when the cavity resonant frequency falls inside the opened photonic stopband as r reaches re, and the transfer of cavity mode energy to inter-particle plasmons when r is further increased.

关 键 词：二维光子晶体 电浆 谐振腔模式 时域有限差分方法 优化 表面等离子 傅立叶频谱 PPC 

分 类 号：TN201[电子电信—物理电子学] TQ323.5[化学工程—合成树脂塑料工业]