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arXiv 1910.04468physics.optics
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双金属核壳纳米粒子在介质基底上的吸收和等离子体共振

Absorption and Plasmon Resonance of Bi-Metallic Core-Shell Nanoparticles on a Dielectric Substrate Near an External Tip

Dilan Avsar, Hakan Erturk, M. Pinar Menguc

摘要:

吸收效率的分布和局部表面等离子体共振(LSPR)波长的金属核-壳纳米粒子(NP)放置在BK 7玻璃基板。数值研究与矢量化版本的离散偶极子近似与表面相互作用(DDA-SI-V)。金(Au)和银(Ag)金属组分用于模拟两种不同的核壳结构。吸收增强和等离子体共振的核-壳结构的混合模式进行比较,通过使用定义的尺寸配置的措施。据观察,一个小的体积分数的核心尺寸的结果在壳的等离子体激元响应的支配。进行额外的研究以辨别纳米颗粒在不同周围环境中的折射率的灵敏度。对于银核-金壳和金核-银壳纳米粒子,在选定的核-壳尺寸结构下,观察到银核-金壳和金核-银壳纳米粒子的LSPR波长红移。还分析了裸露的金属纳米颗粒和所选的核-壳对在外部探针附近的吸收行为。利用横向电场(TE)和横向磁场(TM)波极化研究了磷化镓(GaP)和硅(Si)AFM针尖的使用。据观察,光偏振的吸收增强的NPs开关在不同的波长,其中尖端材料的介电转变发生的优势。这些发现显示了金属核-壳纳米颗粒在几个领域的可能目标用途,如纳米制造,局部加热,生物传感和材料检测应用。

英文摘要:

Absorption efficiency profiles and localized surface plasmon resonance (LSPR) wavelengths are reported for metallic core-shell nanoparticles (NPs) placed over a BK7 glass substrate. A numerical study is performed with the vectorized version of the discrete dipole approximation with surface interactions (DDA-SI-v). Gold (Au) and silver (Ag) metallic components are used for the simulations of two different core-shell structures. Absorption enhancement and the hybrid modes of plasmon resonances of the core-shell structures are compared by using a measure that defines a size configuration. It is observed that a small volume fraction of the core sizes results in shell domination over the plasmon response. An additional study is conducted to discern the sensitivity of the refractive index of nanoparticles in different surrounding environments. With a selected core-shell size configuration of Ag-Au pairs, a significant absorption enhancement with a redshift of LSPR wavelength is observed for both Ag core-Au shell and Au core-Ag shell NPs. The absorption behavior of the bare metallic NPs and selected core-shell pairs in proximity to an external probe is also analyzed. The gallium phosphide (GaP) and silicon (Si) AFM tip usage are investigated with transverse electric (TE) and transverse magnetic (TM) wave polarizations. It is observed that the dominance of light polarization on the absorption enhancement of the NPs switches at different wavelengths, where the dielectric transition for tip materials occurs. These findings show the possible targeted uses of metallic core-shell nanoparticles in several areas such as nanomanufacturing, localized heating, bio-sensing, and material detection applications.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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