Joining organic molecules and metallic nanoparticles into coupled heterostruc-tures allows tuning their optical properties and o®ers novel possibilities for manipulating theiremission patterns. This Master Thesis is aimed at probing and understanding the nature ofthe optical coupling between plasmonic nanoparticles and organic molecules. We carry outsecond harmonic spectroscopy and interferometry experiments on thin flms of the nonlineardye crystal violet deposited on glass and on top of silver nanoparticles to study the interplaybetween the resonance of the dye and the plasmon modes of the nanoparticles. We find asmall redshift of second harmonic emission from the nanoparticles, while the molecular second harmonic resonance displays a large blueshift of tens of nanometers in the vicinity of thenanoparticles. Across both resonances a characteristic shift of ¼ in the phase of the generatedsecond harmonic light is observed by second harmonic interferometry. To explain our ¯nd-ings, a phenomenological model with two coupled damped anharmonic oscillators is proposed.With the model, we are able to reproduce the main features of the experimental data.

Projecte fet en col.laboració amb l'Institut de Ciències Fotòniques