# Localized Surface Plasmon Fields Manipulation on Nanostructures Using Wavelength Shifting
## 3 Results
Figure 3: Simulation results of plasmonic near-field electromagnetic fields distributions for T-shaped nanostructure arrays by incident light with wavelengths of (**a**) 1550, (**b**) 1310, (**c**) 1064, and (**d**) 808 nm. Intensities of localized electromagnetic fields at (**e**) the edge (profiled line (1)) and (**f**) the center (profile line (2)). The information of incident light source is indicated in (**b**). To vary the confined field mode on the same structure array, there is another main variable regarding the incident light source. The polarization of the incident light source also can be considered for achieving additional diverse modes of the confined field on the structures. From the data presented in Figures 2-4 are the simulated results with TM mode of incident light at 60 incident angle degrees in xz-plane. However, we performed the further calculation of field confinement on the structure arrays when the structures are illuminated by 4 different wavelengths of TE mode incident light source while maintaining incident angle degree in xz-plane, and the results are presented in Figure 5. Interestingly, a different mode of the generated confined field from that achieved by TM mode was observed using TE mode illumination as shown in Figure 5 as top-view. The results show that with the different polarization of incident field, TE mode in this case, on/off mode of the confined field on the I- and Y-shaped structure depending on the wavelength was observed as shown in Figure 5b,d. The longer wavelength highly confined the field on the structure while off-mode was observed with shorter wavelength in TE mode. On the other hand, hard to find big difference in T-shaped structures. Figure 4: Simulation results of plasmonic near-field electromagnetic fields distributions for T-shaped nanostructure arrays by incident light with wavelengths of **(a)** 1550, **(b)** 1310, **(c)** 1064, and **(d)** 808 nm. **(e)** Intensities of localized electromagnetic fields at **(e)** the edge (profiled line (1)) and **(f)** the center (profile line (2)). The information of incident light source is indicated in **(b)**. There could be another way for confined field switching on the structures or scanning of the spatial field along with the structures while maintaining pattern geometry, which is the orientations of the incident light source. It is well known that the resonance condition of ellipsoidal nanoparticles varies depending on their aspect ratio and the orientations of incident light source without any deformation of particles [40] since an additional geometric issue can be provided to the designed structure array without modifying the geometries of the pattern by providing light source orientation. In this regard, orientation of light source was selected for supplying versatile mode achievement. A simulation was executed using diverse orientations of the incident light source while maintaining incident angle as 60\({}^{\circ}\) to give extra geometrical input to the structure generating versatile formations of field confinement. The range of incident light orientations which can be indicated in xy-plane was set between 0\({}^{\circ}\) to 40\({}^{\circ}\) with respect to the \(x\)-axis as indicated in the left part of Figure 6. Depending on the orientation, we designated with a lowercase alphabet and the calculated results are shown in the right part of Figure 6a-j. As shown in the results, scanning of the field localization was observed along the structures also the discrete localization of field was found. This scheme can be practically applied for a resolution enhanced imaging collaborating a method introduced in [41] which utilizes multi-channel spatial excitation. Figure 5: A front view of schematic is shown in (**a**). The TE mode of incident light at 60 incident angle degree is illustrated.