Nanofocusing performance of plasmonic probes based on gradient permittivity materials
Journal of Optics
Probe is the core component of an optical scanning probe microscope such as scattering-type scanning near-field optical microscopy (s-SNOM). Its ability of concentrating and localizing light determines the detection sensitivity of nanoscale spectroscopy. In this paper, a novel plasmonic probe made of a gradient permittivity material (GPM) is proposed and its nanofocusing performance is studied theoretically and numerically. Compared with conventional plasmonic probes, this probe has at least two outstanding advantages: first, it does not need extra structures for surface plasmon polaritons excitation or localized surface plasmon resonance, simplifying the probe system; second, the inherent nanofocusing effects of the conical probe structure can be further reinforced dramatically by designing the distribution of the probe permittivity. As a result, the strong near-field enhancement and localization at the tip apex improve both spectral sensitivity and spatial resolution of a s-SNOM. We also numerically demonstrate that a GPM probe as well as its enhanced nanofocusing effects can be realized by conventional semiconductor materials with designed doping distributions. The proposed novel plasmonic probe promises to facilitate subsequent nanoscale spectroscopy applications.
This is the Accepted Manuscript version of an article accepted for publication in Journal of Optics. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/2040-8986/ac69f6. This article will be embargoed until 05/06/2023.
Nanofocusing , Plasmonic probe , gradient permittivity material , surface plasmon polaritons , field enhancement and localization
Wang, Dongxue, Ze Zhang, Jianwei Wang, Ke Ma, Hua Gao, and Xi Wang. 2022. “Nanofocusing Performance of Plasmonic Probes Based on Gradient Permittivity Materials.” Journal of Optics 24 (6): 065003. https://doi.org/10.1088/2040-8986/ac69f6.