Local crystallization of a resonant amorphous silicon nanoparticle for the implementation of optical nanothermometry

Local optical heating and Raman nanothermometry based on resonant silicon particles provide a new promising platform for a number of key nanophotonics applications associated with thermally induced processes at the nano- and microscale. In this work, the crystallization of amorphous silicon nanodisks with optical resonances caused by local optical heating has been studied. The crystallization process is controlled by Raman microspectroscopy. The crystallization temperature of a single nanodisk of about 900 K has been determined under the action of a strongly focused cw laser beam. As a result, an annealed resonant silicon nanoparticle has allowed controlled and reversible heating in the temperature range of 300–1000 K with the possibility of mapping the heating region with submicron spatial resolution.