Pseudo-Chiral Resonators for the Optical Detection of Chiral Molecules – ChiROptMol

Photonic nanoresonators feature the ability to resonantly interact with light and are characterized by moderate quality factors and small effective volumes. This resonant interaction leads to an increase of the light scattering (far field) and of the field intensity in the vicinity of the resonators (near field). Metallic nanostructures hosting localized surface plasmons have been widely investigated to enhance light matter interactions.
Near field: The enhancement of the near electric field in the vicinity of the photonic resonators is used in sensors to allow for more efficient coupling with light and increase the excitation rate of molecules. This light-matter enhancement is the key to probe molecules with high sensitivity (toward the single molecule resolution). The engineering of the near-field symmetries is a promising emerging topic in the enhancement of the detection sensitivity.
Far field: the symmetries of the near-field interaction with chiral molecules are transferred to the angular repartition, spectral dependence and polarimetric properties of the field scattered in the radiation region. The understanding of the relations between the near-field and chiral molecules allow proposing a new class of plasmonic resonators for the detection of biomolecules.
The CHirOptMol aims at exploiting the resonant optical responses of metallic nanostructures to enhance light matter interactions via the helicity of light. Circular polarization has always played a key role in light matter interactions, in particular to detect chiral molecules with respect to the helicity of light. Symmetric planar structures called pseudo-chiral nanostructures, such as U-shaped scatterers, are very interesting since they can be organized onto planar metasurfaces. They present the great advantage over chiral nanostructures to boost a different circular dichroism for unpolarized light depending on the direction of propagation. The complex interaction between chiral emitters and pseudo-chiral nanostructures has not yet been described analytically. One of the biggest challenges is to calculate each element of the polarizability tensor of (i) resonant pseudo-chiral nanostructures and of (ii) interacting pseudo-chiral and chiral nanostructures or molecules.
The CHirOptMol project aims at exploiting the optical activity of photonic nanoscatterers to develop groundbreaking techniques in the detection of chiral biological molecules.
This objective consists of using pseudo-chiral nanostructures to realize highly sensitive compact biosensors with sensitivity depending on the enantiomer detected. The same detector could thereby detect both the presence and the handedness of biomolecules.Different biomolecules known for their importance in biology will be tested.