![]() used the localized thermal heating effect induced by the plasmonic coupling of silica coated gold and Fe 2O 3 nanoparticles to kill cancer cells. utilized the local temperature rise that results from plasmonic modes in metallic nanostructures to grow semiconductor nanowires and carbon nanotubes. 6,7 However, through the excitation of plasmonic resonances in certain metamaterials, the diffraction limit can be overcome to obtain hot spots on the order of tens of nanometers. 1 This hot spot is too large for some applications such as nanoscale patterning, 2 photothermal therapy, 3–5 and super high areal density data recording. The spot size of an optically focused light is constrained by the Abbe diffraction limit, which in turn limits the hot spot size that can be generated by the focused light or laser. Furthermore, the transient temperature profile shows that the system reached steady state within ∼0.36 μs. This clearly demonstrates plasmonic localized heating beyond the diffraction limit via magnetic polariton excitation. Moreover, the temperature rise from ambient drops to half its maximum value at a distance of 5 nm from the top of the spacer along the z-direction. ![]() The steady state temperature profile shows an average temperature of 145 ☌ confined in a local area as small as 33 nm within the spacer, with a full-width at half-maximum of 50 nm along the x-direction. Volume loss density due to the strong local optical energy confinement was transferred as heat generation to an ANSYS thermal solver to obtain the local temperature profile. An inductor-capacitor circuit model was used to predict the magnetic resonance wavelength and compare with the numerical results for varied geometrical parameters. A strong absorption peak at the wavelength of 760 nm was exhibited, and the underlying physical mechanism for the strong absorption was verified via the local electromagnetic field distribution to be magnetic resonance excitation. In this work, we numerically investigated the optical response of a nanoscale metamaterial composed of a gold nanowire array and a gold film separated by an ultrathin polymer spacer using ANSYS High Frequency Structural Simulator. However, achieving plasmonic localized heating by the excitation of magnetic polariton has not been researched extensively yet. Plasmonic approaches to overcome the diffraction limit in hot spot size have mainly utilized the excitation of surface plasmon or localized surface plasmon resonance. Plasmonic localized heating can provide solutions to this limitation in nanoscale patterning, cancer treatment, and data storage. However, the hot spot size is conventionally constrained by the diffraction limit. Optical localized heating in the nanoscale has recently attracted great attention due to its unique small hot spot size with high energy.
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