Enhancement of inherent Raman scattering in dielectric nanostructures with electric and magnetic Mie resonances

Abstract: Resonantly enhanced Raman scattering in dielectric nanostructures has been recently proven to be an effcient tool for developing nanothermometry and experimental determination of their mode- composition. In this paper, we develop a rigorous analytical theory based on the Green's function approach to calculate the Raman emission from crystalline high-index dielectric nanoparticles. As an example, we consider silicon nanoparticles which have a strong Raman response due to active optical phonon modes. We relate enhancement of Raman signal emission to Purcell effect due to the excitation of Mie modes inside the nanoparticles. We also employ the numerical approach to the calculation of inelastic Raman emission in more sophisticated geometries, which do not allow a straightforward analytical form of the Green's function description. The Raman response from a silicon nanodisk has been analyzed within the proposed method, and the contribution of the various Mie modes has been revealed.