| Modeling the Near-field Coupling Effects in Scattering Type Near Field Optical Microscopy of Gold Nanodisks |
| Paper ID : 1209-UFGNSM-FULL |
| Authors: |
|
Bizhan Rashidian *1, hesam heydarian2, Afsaneh Shahmansouri3, Payam Yazdanfar3 1Sharif University of Technology, Azadi Ave., Tehran, Iran
PO Box: 11365-11155 2Sharif University of Technology, Azadi Ave., Tehran, Iran.
PO Box: 11365-11155 3Department of Electrical Engineering, Sharif University of Technology |
| Abstract: |
| Although scanning near-field optical microscopy (SNOM) can, in principle, measure both the near field amplitude and phase of the sample of interest in subwavelength scale, optical interaction between the probe of SNOM and the nanostructure under test (such as a plasmonic nanostructure) may distort the measurement. In this paper, near field optical behavior of gold nano disk in the presence of the SNOM probe is investigated numerically. Finite difference time domain method (FDTD) has been used to study near-field coupling between apertureless SNOM probe, and the plasmonic nanostructures in the fundamental plasmon resonance wavelength. We study how the material of the probe and also distance of the probe and gold nano disk, affect the electric near-field distribution of the sample under far-field illumination. The results show that in the presence of the apertureless SNOM tip, the local electric field of the gold nano disk beneath the tip is greatly increased. Indeed, a narrow opening between two metallic nanostructures, probe’s tip and gold nano disk, leads to unwanted electromagnetic field confinement and enhancement. We show that, this local electric field distortion could be decreased by increasing probe-sample distance to about 20 nm, or by employing dielectric probes instead of conventional metal ones. |
| Keywords: |
| Near-field optical microscopy, Plasmonics, Near-field coupling, Characterization |
| Status : Paper Accepted (Poster Presentation) |
