Polarimetric determination of the orientation of a single nano-emitter

Efficient coupling of nanoemitters to photonic or plasmonic structures requires the control of the orientation of the emitting dipoles related to the emitter. Nevertheless the knowledge of the dipole orientation remains an experimental challenge. Many experiments rely on the realization of large sets of samples, in order to be able to get one nanostructure coupled to a well aligned dipole. In order to avoid these statistical trials, the knowledge of the nature of the emitter (single or double dipole) and its orientation are both crucial for a deterministic approach. Based on the theoretical development of the point-dipole emission, we propose in this paper to determine the nature and the polarization of two types of nanoemitters (spherical nanocrystals and dot-in-rod) by the analysis of their emission polarization [1,2]. The nanoemitters we considered in this study are colloidal semiconductor (CdSe/CdS) nanocrystals with different sizes and aspect ratio, allowing us to establish a relationship between the geometry of a nanoemitter and the nature and orientation of its associated radiating dipole.