Eremin Yuri, Doicu Adrian, Wriedt Thomas
J Opt Soc Am A Opt Image Sci Vis. 2020 Jul 1;37(7):1135-1142. doi: 10.1364/JOSAA.392537.
Over the last few decades, dielectric core and metallic plasmonic shell (Die@Me) nanoparticles have found a wide variety of applications. The trend to reduce the thickness of the metallic coating requires to account for the influence of the nonlocal dispersion on the spectral response of such nanoparticles. In this paper, we use the discrete sources method and the generalized nonlocal optical response model to describe the nonlocality within the plasmonic metal shell. We found that the variation of the plasmonic shell thickness and the elongation of the nonspherical core-shell particle can enlarge the near-field enhancement and the absorption cross section by an order of magnitude. Besides, we show that the nonlocal dispersion can decrease the field enhancement in the wavelength domain up to 2.5 times with a small blue-shift of about 5 nm.
在过去几十年中，介电核与金属等离子体壳层（Die@Me）纳米粒子已获得广泛应用。降低金属涂层厚度的趋势要求考虑非局域色散对此类纳米粒子光谱响应的影响。在本文中，我们使用离散源方法和广义非局域光学响应模型来描述等离子体金属壳层内的非局域性。我们发现，等离子体壳层厚度的变化以及非球形核壳粒子的伸长可使近场增强和吸收截面增大一个数量级。此外，我们表明非局域色散可在波长域将场增强降低至2.5倍，同时伴有约5 nm的小蓝移。
