Institut des
NanoSciences de Paris

Nano-enhanced probes for Near-field Scanning Optical Microscopy

In collaboration with the Langevin institute in Paris and the ICFO institute in Barcelona we study, at the fundamental level, the coupling between optical nanoantennas and fluorescent emitters through the use of Near Field Optical Microscopy.

Near-field scanning optical microscopy (NSOM/SNOM) is a microscopy technique for nanostructure investigation that breaks the far field resolution limit by exploiting the properties of evanescent waves. Since the 80’s, the NSOM has been mainly used as a technique to optically characterize samples in near field, following different approaches as emission, collection and scattering amongst others. Recently, the improvement of nanoscale fabrication has brought new interest to this field by allowing new properties and functionalities to nanostructured near-field tips. In particular, the nanofabrication of specifically designed resonant optical nanoantennas (figure 1) has opened new avenues and applications to the nano-optics community.

Figure 1 : SEM images of nano-enhanced probes fabricated at the apex of near field tips.

In our group, we focus on the concept, fabrication and use of such nano-enhanced near-field probes. In particular, we develop optical nanoantennas carved at the apex of a near field tip to study, at the fundamental level, the interaction between resonant optical nano-structures and fluorescent emitters. We are especially interested in studying the emission of magnetic dipolar transitions (figure 2), FRET pairs, and single fluorescent molecules using these nano-enhanced probes.

Figure 2 : The illustration represents a photonic nanoantenna together with a crystal containing a magnetic dipole on top. The intense and bright spot represents the magnetic dipole, and the sparks symbolize the enhanced radiative emission of the latter.


Collaborations :

- Sébastien Bidault at the Institut Langevin (ESPCI, Paris)

- Maria Garcia-Parajo at the ICFO (Barcelona)

- Thierry Grosjean at FEMTO-ST (Besançon)