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Meta 2010 & FEM 2010 – Rome, 13-15 December 2010 Optimized second harmonic generation in gold square rod chains Marco Centini, Alessio Benedetti, Concita Sibilia, Mario Bertolotti Dipartimento di Scienze di Base e Applicate per l'Ingegneria- Sez Fisica. Sapienza Università di Roma. Via A. Scarpa 16 00161 Roma – Italy E-mail: marco.centini@uniroma1.it Thanks to the development of nanotechnologies and nanoscience, nonlinear properties of metallic nanostructures have been deeply investigated both theoretically and experimentally in the last years. SHG enhancement from nanoantennas and nanodimers has been observed both in near and far fields[1,2]. In a recent work we studied SHG in gold nanowires pointing out the possibility to tailor the properties of the generated signal by proper design of the system [3]. The same method developed in [3] has been used to investigate SHG by a chain of gold rods. Here we report the results of our calculations by considering, as an example, a chain made of five gold rods (figure 1a). We show that strong field localizations are obtained in the region between the rods resulting from interference of localized surface plasmons when the fundamental field is tuned on a coupled resonance (figure 1a). This effect provides a more efficient coupling of the pump energy to plasmon modes and is responsible of the enhancement of second harmonic generated signal (figure 1b). 40 150 210 120 240 90 270 3e-018 2e-018 1e-018 4e-018 180 0 c) b) Figure 1: (a) modulus of the magnetic field H normalized with respect to the amplitude of the incident field. Fundamental field wavelength is 770 nm, rod sections are 120x120 nm2 and gaps between rods are 15 nm. (b) polar plot of the nonlinear differential scattering cross section for the generated second harmonic field. Typical values of the nonlinear scattering cross section by a gold flat surface at the same wavelength are of the order of 10 -20 cm 2 /W. References [1] B. K. Canfield et al., Nano Letters, 7, 5, 1251-1255 (2007) [2] T. Hanke et al., Phys. Rev. Lett. 103, 257404 (2009). [3] A. Benedetti et al., JOSA B 27, 3, 408-416 (2010)). 60 300 30 330
Meta 2010 & FEM 2010 – Rome, 13-15 December 2010 Tuning Concept of PDMS Nanocomposite Material for Optical Fiber Enhancement Alessandro Massaro (1) , Fabrizio Spano (1) , Roberto Cingolani (2) , and Athanassia Athanassiou (1),(3) (1) Italian Institute of Technology IIT, Center of Biomolecular Nanotechnologies Arnesano (Le), Italy – E-mail: alessandro.massaro@iit.it (2) Italian Institute of Technology IIT- Genova- Italy. (3) National Nanotechnology Laboratory, CNR Institute of Nanoscience Lecce, IT In this work we propose a new design approach of nanocomposite material design by means of tuning of concentration of micro-nanoparticles in a polymeric material. The method is based on the control of the optical enhancement by changing the gold concentration (indicated by the volume filling factor �). We consider as material the Polydimethylsiloxane (PDMS) polymer film due to its ability to generate gold nanoparticles starting from gold precursors by chemical reduction [1]-[3]. A key parameter used for the design is the scattering efficiency. Figure 1 (a) shows the calculated scattering efficiency for different gold concentration ��and Fig. 2 (b)�indicates an application useful for probe detection systems (light enhancement), of an optical fiber embedded in the PDMS-Au. The peaks of Fig. 1 (a) indicate the working wavelength of the optical fiber. 1 (a) (b) Q scatt. 0 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 �[�m] � �� 41 Optical fiber embeddedin PDMS‐Au nanocomposite Figure 1 – a) PDMS-Au scattering efficiency versus the working wavelength for different gold micro/nanoparticles concentration ��in PDMS material. b) Enhanced light of an optical fiber end embedded in PDMS-Au nanocomposite material. References [1] Q. Zhang, J. J. Xu, Y. Liu, and H. Y. Cuen, “In-situ synthesis of poly(dimethylsiloxane)- gold nanoparticles composite filmsand its application in microfluidic system,” Lab on chip, 8, 352-357, 2008. [2] C. E. Hoppe, C. Ridriguez-Abreu, M. Lazzari, M. A. Lopez-Quintela, and C. Solans, “One-pot preparation of gold-elastomer nanocomposites using PDMS- graft – PEO copolymer micelles as nanoreactors ,” Phys. Stat. Sol. (a), 205, 1455-1459, 2008. [3] A. Goyal, A. Kumar, P. K. Patra, S. Mahendra, S. Tabatabaei, P. J. J. Alvarez, G. Jhon, and P. M. Ajayan, “In situ synthesis of metal nanoparticles embedded free standing multifunctional PDMS films,” Macromol. Rapid Commun., 30, 1116-1122, 2009.
Page 1 and 2: Meta 2010 & FEM 2010 - Rome, 13-15
Page 3 and 4: Meta 2010 - Committees Chairmen Met
Page 7 and 8: Meta 2010 Foreword Ladies and Gentl
Page 9 and 10: FEM 2010 Foreword Ladies and Gentle
Page 25 and 26: Session FEM-1 Magnetic device model
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Page 43 and 44: Session FEM-3 Methods and solvers M
Page 47 and 48: Session FEM-4 Design and applicatio
Page 67 and 68: Author Index Meta 2010 & FEM 2010 -

Abstracts - Dipartimento di Elettronica Applicata

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