SMILEs
STRUCTURAL MOLECULAR IMAGING LIGHT ENHANCED SPECTROSCOPIES

People

Marco Allione

Research Scientists

Introduction

Marco is interested in the study of the optical properties of materials and biological systems, with particular relevance to their nonlinear optical properties, nonlinear characterization and microscopy. He is also interested in nanofabrication and in the techniques for the realization of micro- and nano-structured materials.

Research Interests

Sub-diffraction limited Coherent Anti-Stokes Raman scattering from the tip of a plasmonic nanocone
We try to demonstrate, for the first time to our knowledge, the possibility to detect the Coherent Anti-Stokes Raman Scattering (CARS) signal from the tip of a plasmonic nanocone with sub-diffraction resolution. CARS is a technique in which  two light beams, called Pump and Stokes beams separated by a frequency difference f\-pump - f\-Stokes = df, are combined to obtain a third pulse by nonlinear interaction into a sample, which has a different frequency f\-anti-Stokes =f\-pump + df every time the frequency difference df is resonant with a Raman-Active vibrational frequency of the material under investigation. Our goal is to couple the two exciting fields into the propagating modes of a metallic nanocone. The two plasmonic waves induced at the surface of the nanocone propagate up to its distal apex while experiencing adiabatic compression of the electromagnetic field. The nonlinear interaction of the two beams at the tip is expected to lead to the generation of an Anti-Stokes signal confined at the tip apex, thus paving the way to the development of nonlinear coherent Raman spectroscopy at nanoscale.
 

Controlled deposition of DNA molecules on superhydrophobic surfaces
We already reported in previous publications on the possibility to obtain microfabricated surfaces that show super-hydrophobic behavior. These are made of regular arrays of cylindrical pillars obtained in silicon substrates by means of standard optical lithography techniques, with different size of pillars, reciprocal distance, and periodical arrangement. Structures can be fabricated having either the whole surface coated by a hydrophobic layer or, alternatively, having the top of the pillar made with a hydrophilic material, while the rest of the structure surface is hydrophobically coated. We have already a long record of research on these systems on how filaments of DNA previously in solution suspend between pillars upon drop evaporation. The goal of this activity is now to analyze for different structure geometries and surface types the way DNA filaments are suspended as a function of the speed with which the drop of DNA solution was drag on the surface. Another objective is also to analyze the motion of the liquid inside the drop to reveal the way the laminar fluxes inside the liquid affect this deposition. This shall reveal important information on the way to control the deposition of ordered DNA filaments on these substrates.

Selected Publications

M. Allione, A. Ballester, H. Li, A. Comin, J.L. Movilla, J.I. Climente, L. Manna and I. Moreels “Two-Photon-Induced Blue Shift of Core and Shell Optical Transitions in Colloidal CdSe/CdS Quasi-Type II Quantum Rods” ACSNano 7, 2443 (2013).

W. Dallari, M. Scotto d’Abbusco, M. Zanella, S. Marras, L. Manna, A. Diaspro, and M. Allione “Light-Induced Inhibition of Photoluminescence Emission of Core/Shell Semiconductor Nanorods and Its Application for Optical Data Storage” Jour. Phys. Chem. C 116, 25576 (2012).

M. Allione, B. Torre, A. Casu, A. Falqui, P. Piacenza, R. Di Corato, T. Pellegrino, A. Diaspro, “Rod-shaped nanostructures based on superparamagnetic nanocrystals as viscosity sensors in liquid” Jour. Appl. Phys. 110, 064907 (2011).

M. Allione, R. Kofman, F. Celestini, Y. Lereah “Size effect on melting and wetting in the Ga-Pb nano-alloy” Eur. Phys. Jour. D 52, 207 (2009).

M. Allione, V.V. Temnov, Y. Fedutik, U. Woggon, M.V. Artemyev “Surface plasmon mediated interference phenomena in low-Q silver nanowire cavities” Nano Lett. 8, 31 (2008).

Education

2001-2004 Ph.D. in Physics, Dept. Of Physics, Univ. of Pavia, Pavia, Italy

1996-2001 Master in Physics, Dept. Of Physics, Univ. of Pavia, Pavia, Italy