Plasmonic nanostructures have applications in many different areas such as SERS, second harmonic generation, and chemical sensing due to their strong field enhancement and localization at the nanometer scale. Non-radiative plasmonic damping is usually considered a drawback in the utilization of plasmonic structures for light manipulation as it curbs large field enhancements. Most of the energy absorbed by the plasmon will create hot carriers and will eventually generate heat that is coupled to the surrounding medium. In this work, we use photothermal contrast imaging coupled with discrete dipole approximation simulations to characterize the heat localization of plasmonic dimers. We further demonstrate that the heat localization can be tuned at the nanometer scale by changing the wavelength and polarization of the incident light. This is the first demonstration of active control over the thermal near-field surrounding nanostructures. Controllable heat localization at the nanoscale will have important applications in heat-assisted magnetic recording, nanoscale material manipulation, and in thermally driven chemical and biological reactions. By designing these nano-heaters, a new platform for performing chemical and physical changes is provided.

Active binary control of the thermal near field via plasmon hybridization

2019 Fall National Meeting

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