Exploring magneto-optical properties in plasmonic and magnetoplasmonic nanostructures

Plasmonic nanostructures are intriguing materials for applications in optical sensing and enhanced spectroscopies. To further improve their performances, one of the most appealing strategies is the active modulation of the plasmonic response by means of an external magnetic field, i.e.magnetoplasmonics. To reach such a controlled magnetic modulation, the accurate design of the nanostructures in terms of architecture and material choice is crucial. Indeed, conventional plasmonic materials typically display poor magnetic field response, while the insertion of magnetic materials usually damps the plasmonic resonance in hybrid systems. In this thesis, Magnetic Circular Dichroism is employed as a characterization tool to assess the magnitude of the magnetic modulation of the plasmonic resonance in properly designed nanostructures, and some of the key aspects involved in the enhancement of the modulation are highlighted. Colloidal chemistry approaches are almost exclusively exploited to prepare such nanostructures. The investigation covers a wide range of materials and architectures, from purely plasmonic nanomaterials (noble metals and degenerately doped semiconductors) to complex hybrid nanostructures with different degree of interaction between the plasmonic and the magnetic material (mainly core@shell and nanoalloys).