Plasmonic Tips for Near Field Optics – PlasTips

This project is dedicated to the realization, characterization and optimization of plasmonic probes for near field optics. Plasmonic probes consists of metallic structures deposited on an elongated optical fiber. Indeed, metallic structures are well-known to support surface plasmon polariton modes (SPP) that couples an electromagnetic wave to a collective oscillation of the free electrons of the metal. Such mode are characterized by strong electromagnetic field localization and enhancement so that they appears as very promissing materials for high integrated photonics, biosensing or photovoltaics cells applications. Two complementary approaches will be considered ; 1) Structuration of the plasmonic film onto the probe ( top-down aproach): a metal film will be deposited on an elongated optical fiber. This film will be structured using gratings and/or grooves designed in such a way that the grating period insures a good coupling between the fiber and plasmon mode wavectors and that grooves orientation focus the plasmon mode towards the probe apex. 2) Chemical synthesis of plasmonic structures (bottom-up approach). Using chemically synthetized metallic structures, we will benefit of both crystallinity of the metal and very small radius of curvature, leading to extremily high field enhancement. However, in this case, the shape of the metallic structure is limited to highly symmetric systems such spherical, elliptical or nanorod nanoparticles. During this project, we also plan to characterize the coupling between a single quantum emitter and the plasmonic probes. This would lead to the realization of a single photon source directly coupled to an optical fiber. Finally, it is important to mention that two different spectral regims will be investigated: optimizing plasmonic probes in the visible range would lead to direct applications for biological labelling sensitivity and data storage capacities whereas optimization for near infrared is a step towards telecommunication applications.