Sensing Phase Transitions in Solids Using Thermoplasmonics.

We propose an approach to controlling the heating of plasmonic nanostructures by nanostructuring the thermostat surface. We demonstrate this using a two-dimensional array of TiN:Si voxels, which are a system of stacked titanium nitride and silicon nanocylinders. The optical heating of plasmon nanostructures can be directly controlled by the height of silicon columns at a fixed value of the pump intensity. The height of silicon nanopillar sets the operating temperature range, while the pumping intensity allows one to control the temperature in this range. We register this effect using Raman thermometry. Using plasmonic metasurface with array of TiN:Si voxels, we demonstrate the detection of the such phase transitions in nanoconfined polymers as the glass transition temperature and melting temperature at the nanoscale using Raman spectroscopy. [ABSTRACT FROM AUTHOR]