Probing the Orientation of Fluorescent Nanoplatelets for Vertical Orientation

Efficient coupling of nanoemitters to photonic or plasmonic structures requires spatial and spectral matching and the control of the orientation of the emitting dipoles. Whereas spectral matching can be easily obtained in plasmonics and whereas several strategies aim to achieve control of the emitter location inside nanostructures, the control of orientation still remains a challenge Nevertheless depending of the emitting dipole orientation, the light matter interaction between can switch from a quasi nul value to a large interaction with plenty of positive outcomes on the emission characteristics (emission diagram, brightness, dynamics...). Therefore, many experiments try to face this major problem by statistics. They rely on the realization of numerous samples, in order to be able to statistically get a well aligned dipole to realize an efficient coupling to a nanostructure. In order to avoid these statistical trials, the knowledge of the nature of the emitter and its orientation is crucial for a deterministically approach for nanolithography. We have developed a method relying on the combination of polarimetric measurement and emission diagram which gives fine information both on the emitting dipolar transition involved and on the dipolar orientation. In this talk, we first demonstrate that single rectangular colloidal CdSe/CdS nanoplatetelets present polarized emission due to dielectric effect correlated to their rectangular shape anisotropy. We then illustrate the that with cubic nanoplatelets, the achievement of vertical emitting dipoles, optimally coupled to plasmonic surfaces, can be obtained with a good probability. We will then present how such a protocol can be implemented in in-situ deterministic realization of antennas.