Materials having dimensions of nanometers  (10-9m) such as Nanoparticles (NPs), show optical properties which are related to their size and shape. NPs of metals display a collective electronic excitation (plasmon) when an UV-Vis radiation interacts with them. This effect is named Localized Surface Plasmon Resonance (LSPR) where the resonant frequency is tightly depending on the morphological properties of the NPs. Such resonant frequency can be tuned changing  either the NPs’ aggregation or the refraction index of the medium surrounding them. Consequently, the NPs can be successfully employed as sensors able to detect, in a highly selective and sensitive manner, the presence of specific target compounds (analytes) by displaying a variation on the NPs’ optical properties. In this framework, the ISM is developing research activities on NPs’ generation for chemical, environmental sensors and bio-sensors, and on their characterization features. With this aim, microscopic and spectroscopic techniques with high spatial (HR-TEM) and temporal resolution (femtosecond) both in fluorescence (TCSPC and Up-conversion) and in absorption (Pump&Probe) are, respectively, used.

Staff: A. Guarnaccio, D. Mollica, A. Morone, S. Orlando, G.P. Parisi, A. Santagata   

This technology has been patented as a technique to study by optical means the formation of nanoparticles in metallic surfaces or alloys. The presence of nanoparticles modifies the vis/NIR spectrum, affecting particular spectral regions. The formation of nanoparticles is particularly important because it is associated to a phase transition of the metal towards a martensitic structure and produces stiffening of the metal. This latter is important for several industrial purposes and could lead to real-time monitoring of metal stiffening process directly in-situ in the production line and to a quality control overcoming the limitations of destructive and random sampling. The use of this technology will lead to the development of tools to measure the surface stiffness, with advantages in terms of ease of use, cost and versatility. The main limitation is the penetration of light inside the material that, for metals, is tipically a few microns. This makes the analysis basically an investigation of surface stiffening.

Staff: Marco Girasole, Giovanni Longo, Simone Dinarelli, Pierfrancesco Moretti 

The Eurofel Support Laboratory research team has been combining its expertise in ultrafast optics with the manipulation of nanomaterials through plasmonics to investigate and develop novel new methods of nanofabrication. The basis of the approach is to use the ultrafast laser to thermally heat metal nanoparticles and to guide their melting in a controlled form to create new nanostructures. This new field of thermoplas-monics will certainly lead to the development of new nanofabrication techniques with applications in many different fields including metamaterials, sensors, catalysis, photo-thermal therapies, substrates for surface enhanced spectro-scopies and substrates for non-linear optics.

Staff: D. Catone, P. O’Keeffe, A. Paladini, F. Toschi, S. Turchini  
 

The chiral properties of molecules and supramolecular systems play a fundamental role in the field of chemistry, physics, and biology. Pharmaceutical applications and food market increasingly require pure basic chiral molecules in order to improve the safety of their  industrial products. 
Standard spectroscopic and structural investi-gations on these materials need circularly polarized radiation applied to Optical Rotatory Dispersion and Circular Dichroism to chara-cterize their electronic and structural properties. Recently, adsorption of chiral molecules on metal and semiconductor surfaces and their self-assembling processes are becoming a well established field with application in non-linear optical technology and molecular recognition.
In particular, systems showing surface chirality attract special attention in chemistry and biology  because of specific selectivity of the chiral in-terface at the molecule/surface system opening important applications for enantioselective reactions in enantiomeric catalysis and sensors fields. 

Staff: Giorgio Contini, Daniele Catone, Stefano Turchini, Nicola Zema