Teoria dei Solidi, Fotonica e Nanostrutture (D. Gerace)
Transcription
Teoria dei Solidi, Fotonica e Nanostrutture (D. Gerace)
CNISM Fisica Teorica della Materia, Fotonica & Nanostrutture Dario Gerace Dipartimento di Fisica, Università di Pavia Giornata di orientamento L.M. in Scienze Fisiche - 19 Maggio 2015 Groups and People Ø Computational Statistical Mechanics Prof. S. Romano Prof. L. C. Andreani Ø Photonics & Nanostructures Prof. D. Gerace Prof. M. Liscidini Post-Docs: A. Bozzola, P. Kowalczewski, S. W. Flores PhD students: F. Alpeggiani, S. Del Sorbo, M. Menotti, S. Rafizadeh Master students: V. Introini, D. Kos, M. Passoni, L. Redorici Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics COMPUTATIONAL STATISTICAL MECHANICS Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics Statistical Mechanics Ø Computational research on liquid phases of matter (nematic phases of liquid crystals) Ø Statistical mechanics of spin lattices (also exact demonstrations) Ø Study of thermodynamic and structural properties of systems of interacting many particles RELATED COURSES (L.M. Chimica): Statistical Thermodynamics Theoretical and Computational Chemistry WEBSITE: http://www2.pv.infn.it/~romano/ Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics PHOTONICS Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics Photonic crystals electrons in crystalline solids Schrödinger equation photons in periodic dielectric media 2nd-order Maxwell eqs. for harmonic fields “Photonic bands” and energy gaps, as in solids! Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics Photonic crystal nanocavities Ø Trapping light at the nanoscale SEM of a fabricated device Theoretical modeling Q ~ 106 à τ~1 ns V~(λ/n)3 à |E|2 ~1/V Ø Several applied and fundamental works on enhanced optical nonlinearities in collaboration with optical spectroscopy group (see Guizzetti) Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics Photonic crystals in silicon photonics: grating couplers for telecom applications Our task: optimizing the coupling efficiency from a single-mode optical fiber (longdistance communication) into a silicon optical integrated circuit UGent (2002-) EU project Fabulous Project goal: realizing an Optical Network Unit in silicon photonics à optical modem on a silicon chip! Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics Photovoltaics Ø Photovoltaic conversion in solar cells = optical problem (light trapping) + electronic problem (carrier collection) ⇒ both fundamental aspects (efficiency limits) and applied ones ⇒ cultural opportunities, as well as funding and career ones Ø Projects: public + industrial EU FP7 Marie Curie ITN Network “PROPHET” ENI S.p.A. “Photonics for PV systems based on fluorescent concentrators” Nanophotonics meets Photovoltaics ! Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics Bloch surface waves Ø Theoretical study of optical surface waves in periodic media. M. Menotti and M. Liscidini (a) (b) z nPMMA,h ⇒ e.g., Biosensing applications x y w nTiO2,dfirst nSiO2,dSiO2 Fisica teorica della materia, fotonica e nanostrutture n – Dip. ,d Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics TiO2 TiO2 Quantum Nonlinear Photonics Ø Theorertical studies on the generation and characterization of nonclassical states of light (i.e., entangled, squeezed …), in connection with experiments (see Guizzetti) Ø Connections to Quantum Mechanics, Quantum Computation and Quantum Information (see D’Ariano) A CLASSIC NEVER GETS OLD MARCO LISCIDINI1, J. E. SIPE2 1 2 Department of Physics, University of Pavia, Pavia, Italy Department of Physics, University of Toronto, Toronto; Ontario, Canada Fig. 1 Artistic represe the resolution enhan the characterization o pairs by stimulated e picture is a combinat results of two JSD me of photons generated in an integrated wave The less resolved par by means of a quantu based on coincidence the more resolved im magnifier is obtained classical analog of SD limit of classical mechanics. In this view, when we arrive at the divide between classical and quantum, we are in truly foreign territory. The fundamental concepts we use in physics on a day-to-day basis, such as the presumed separation between experimenter and experimental system [10], are in need of in time, and if this classical-like oscillation is couple electromagnetic field in the usual way emission or can result, depending on the relative phase of the moment and the applied field. Classical-like calcula here mirror the results of full quantum calculations Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics Single-photon sources |e> !ω 0 Ø An ideal single-photon source à | n = 1〉 |g> ω0 Ø Our interest: realizing single-photon sources integrated in silicon chips Ultimately: single-photon devices (transitors, diodes…) Fundamental physics today…applications tomorrow ? Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics ELEMENTARY MATERIAL EXCITATIONS Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics Elementary excitations as quasi-particles Ø Solids are complex systems…but their low-energy excitations can be described in terms of collective degrees of freedom, which can be considered actual particles phonons, excitons, polaritons, plasmons, magnons, … Ø Quantum theories of elementary excitations à QFT e.g. à a Cooper pair phonon Teoria dei solidi, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics Plasmonics dielectric PLASMONS: collective excitations of free electrons in a metal They can LOCALIZE à surface plasmons + - + They can COUPLE TO RADIATION (surface plasmon polaritons) - + metal Vibrant field of research, with many fundamental aspects (control of radiative processes, sub-wavelength optics, classical and quantum phenomena) and applied ones (biosensors…) Electronic systems PLASMONICS Photonics Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics Quantum simulators Ø Digital simulators: Directly computing the time evolution of complex manybody models Elementary unit (qubit): collective spin ensemble in a microwave resonator à MIUR – FIRB project in collaboration with Univ. Parma Ø Analog simulators: Studying systems with formal analogies with models in theoretical physics e.g.: relativistic electrons in graphene, strongly correlated photonic lattices, analog dynamics in curved space-time Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics Research in Condensed Matter Theory FUNDAMENTAL RESEARCH APPLIED RESEARCH Theoretical Physics Statistical Physics Energetics Quantum Mechanics CM theory Quantum optics Quantum electronics Information and Communication Technologies Materials sciences Quantum information processing Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics Research in Condensed Matter Theory Ø Problem solving à trained at developing numerical and/or analytic skills Ø Collaborative works, international environment Fisica teorica della materia, fotonica e nanostrutture – Dip. Fisica, Università di Pavia – http://fisica.unipv.it/nanophotonics