Active tuning of Mie resonances to realize sensitive photothermal measurement of single nanoparticles

Abstract

High-index all-dielectric nanostructures with Mie-type resonances have promising applications in building optical nanodevices and metasurfaces. Very recently, great efforts have been made to explore the effective active tuning of Mie-type magnetic resonances via applied voltages, heating, etc. for more sensitive optoelectronic and photothermal applications. Here, we constructed a new platform containing vanadium dioxide (VO₂) films and tungsten disulfide (WS₂) flakes to realize distinctive active tuning of the collective Mie resonances from silicon nanoparticle (Si NP) clusters and measure the resonance-enhanced local heating precisely. Through increasing the thickness of WS₂, we found new type active spectral evolution with high sensitivity during the phase change of VO₂. The temperature increase caused by local heating of different Si NP clusters can be determined through both scattering and photoluminescence (PL) measurements with the best thermal resolution less than 1 °C. The proposed platform provides a new way to enhance the active tuning of Mie resonance and detect the local heating sensitively. More importantly, we propose a new mechanism for measuring the photothermal effects of single dielectric nanoparticles for future energy and biomedical applications.