局域态密度对表面等离激元特性影响的研究

The effects of local density of states on surface plasmon polaritons

表面等离激元是一种在金属与介质界面上激发并耦合电荷密度起伏的电磁振荡,具有近场增强和短波长等特性,在纳米光子学的研究中扮演重要角色.将表面等离激元的效应用于单元子源的制备,不但可以有效减小器件的体积,而且可以有效提高单光子的辐射和收集效率.本文根据表面等离激元的珀赛尔系数与光子态密度的关系,采用局域态密度计算的方法,分析了不同金属材料的局域态密度及珀赛尔系数的特性.通过计算比较,选择银为最佳金属材料,并在此基础上讨论了探测距离和电介质材料对局域态密度和珀赛尔系数的影响,为基于表面等离子激元的单光子源制备提供重要参数.

Surface plasmon polariton （SPP） is a kind of electromagnetic oscillation coupling due to the undulation of charge intensity, which is excited at the interface between metal and dielectric. With the help of near-field enhancement, surface plasmon polariton plays an important role in nano-photonics. When the effect of SPP is used to fabricate the single photon resource, not only the volume can be miniaturized, but also the single photon radiation and collection efficiency can be effectively improved. According to the relationship between the factor of Purcell effect and the density of states, we calculate the local density of electromagnetic states（LDOS） and Purcell factor. By analyzing the local densities of electromagnetic states of different metallic materials, we find that silver is the most suitable metal. For a certain metal, the detection distance and the dielectric material also have influences on local density of electromagnetic states and Purcell factor, and they provide important parameters for the designing of single photon resource based on surface plasmon resonances.