Photonics in Random Media

In recent years, random lasing materials (e.g. powders, porous media, precipitates in solution, or photonic crystals with impurities) have been extensively studied experimentally. Pumping energy into these systems causes them to re-emit multi-mode coherent light, with a spectrum displaying randomly arranged peaks in frequency. Starting from the structure and geometry of the atoms and molecules that scatter the light waves, one would eventually want a theory that predicts the onset, the nature and the features of the light modes and answering the following questions.

  1. What shape and size do light modes display in space ?
  2. In which dimension and under which conditions do they localize because of disorder?
  3. On which frequencies do light modes emit in cavity-less media?
  4. Can there be a random laser pulse in time?
  5. Do competing random laser modes phase-lock as in multimode standard lasers?
  6. How strong is the coupling magnitude and how is it related to the coupling modes spatial overlap and the etherogeneous optical susceptibility?

The latter two questions are connected to the coupling property of depending on the spatial overlap of the electromagnetic fields of the interacting modes. This feature ascribes to the problem of assessing the structure of an interacting network of light-modes in a statistical mechanics representation. Indeed, a set of modes can interact only if their electromagnetic fields overlap in space and, in the lasing regime, non-linear amplification occurs only if the frequencies of the modes satisfy some kind of mode-locking condition. These rules strongly influence the set of feasible interactions in which each mode is viewed as a network node. A key challenge that we address is the characterization of the structure of this network of wave-modes, including the strengths and signs of the relevant random interactions, as is required, e.g., in order to distinguish apart physical regimes of laser stationary behaviour. To this aim a Hamiltonian theory has been derived and investigated in systems with different kinds of bond-disorder, ranging from standard ordered multimode mode-locking lasers to recently introduced glassy random lasers.

Glassy Random Laser and Experimental Measurement of Replica Symmetry Breaking

The investigation of the glassy behaviour of light in the framework of our theory is made possible by means of a newly introduced overlap parameter, the Intensity Fluctuation Overlap (IFO) measuring the correlation between intensity fluctuations of waves in random media. This order parameter allows to identify the laser transition in arbitrary physical regimes, with varying amount of disorder and non-linearity. In particular, in random media it allows for the identification of the glassy nature of some kind of random laser, in terms of emission spectra data, the only data so far accessible in random laser measurements. The model devised from first principles in whose framework the parameter is defined is the nonlinear phasor statistical mechanical model. This is a generalised complex spherical spin-glass model solvable in the mean-field approximation by Replica Symmetry Breaking theory. IFO measurements are possible in real experiments, recently leading to a validation of the RSB theory and a new characterisation of lasers in terms of spectral intensity fluctuations.

Interference of Coupling of Waves in Random Media

The light modes interaction network has to be inferred starting from data acquired in measurements, of spectra and correlations of phases and amplitudes of the light modes, and this inference problem is closely analogous to those in our other areas of application of statistical inference. Starting with the analysis of the inverse problem in statistical mechanical systems with continuous variables, like XY and complex phasors, our inference project is concerned with the bottom-up approach for studying statistical models for application to wave and optics. The parameters describing a given model system, like active links in the network system and external field affecting the system, are inferred using the data set which is made available by experimental or numerical measurements.

We adopt various inference techniques to reconstruct the interaction networks and to estimate the coupling values: mean-field approach, Pseudo Likelihood Maximization (PLM) with L1 and L2 regularizations and PLM with decimation. Such inverse problems for network reconstruction are considered on graphs of different kinds, from 2D and 3D nearest-neighbour lattices, Bethe and Erdos-Renyi sparse random graph to dense random graphs.

Facilities and Labs

S.Li.M. Lab @ Roma

People

leuzziLuca

Leuzzi

CNR Researcher

fabrizioantenucci_postdocFabrizio

Antenucci

Associate PostDoc

alessiamarruzzo_postdocAlessia

Marruzzo

Associate PostDoc

payaltyagi_postdocPayal

Tyagi

Associate PostDoc

Publications

  1. F Antenucci, Statistical Physics of Wave Interactions,  Springer (2016).
  2. P Tyagi, A Marruzzo, A Pagnani, F Antenucci, L Leuzzi, Regularization and decimation pseudolikelihood approaches to statistical inference in XY-spin models,  Physical Review B 94, 024203 (2016) Doi: 10.1103/PhysRevB.94.024203.
  3. F Antenucci, A Crisanti, M Ibáñez-Berganza, A Marruzzo, L Leuzzi, Statistical mechanics models for multimode lasers and random lasers.  Philosophical Magazine 96, 704-731 (2016) Doi: 10.1080/14786435.2016.1145359.
  4. F Antenucci, MI Berganza, L Leuzzi, Statistical physics of nonlinear wave interaction,  Physical Review B 92, 014204 (2015) Doi: 10.1103/PhysRevB.92.014204 .
  5. P Tyagi, A Pagnani, F Antenucci, M Ibanez Berganza, L Leuzzi, Inference for interacting linear waves in ordered and random media,  Journal of Statistical Mechanics: Theory and Experiment 2015 (5), Doi: 10.1088/1742-5468/2015/05/P05031
  6. F Antenucci, A Crisanti, L Leuzzi, Complex spherical 2+ 4 spin glass: A model for nonlinear optics in random media,  Physical Review A 91, 053816 (2015) Doi: 10.1103/PhysRevA.91.053816.
  7. F Antenucci, MI Berganza, L Leuzzi, Statistical physical theory of mode-locking laser generation with a frequency comb.  Physical Review A 91, 043811 (2015) Doi: 10.1103/PhysRevA.91.043811  .
  8. A Marruzzo, L Leuzzi, Nonlinear XY and p-clock models on sparse random graphs: Mode-locking transition of localized waves,  Physical Review B 91, 054201 (2015) Doi:10.1103/PhysRevB.91.054201 .
  9. F Antenucci, C Conti, A Crisanti, L Leuzzi, General phase diagram of multimodal ordered and disordered lasers in closed and open cavities.  Physical Review Letters 114, 043901 (2015) Doi: 10.1103/PhysRevLett.114.043901 .
  10. N Ghofraniha, I Viola, F Di Maria, G Barbarella, G Gigli, L Leuzzi, C Conti, Experimental evidence of replica symmetry breaking in random lasers,  Nature communications 6, 5 (2015) Doi:10.1038/ncomms7058 .
  11. F Antenucci, A Crisanti, L Leuzzi, The glassy random laser: replica symmetry breaking in the intensity fluctuations of emission spectra,  Scientific reports 5, 16792 (2015) Doi:10.1038/srep16792 .
  12. F Antenucci, M Ibanez Berganza, L Leuzzi, Statistical mechanical theory of mode-locked multimode lasers in closed cavity: determination of thresholds, spectra, pulse phase delays and pulse correlations.  Phys. Rev. A 91, 043811 (2014) Doi: 10.1103/PhysRevA.91.043811.

Other Selected Publications

  1. V Folli, A Puglisi, L Leuzzi, C Conti, Shaken Granular Lasers,  Physical Review Letters 108, 248002   (2012) Doi: 10.1103/PhysRevLett.108.248002.
  2. L Leuzzi, C Conti, V Folli, L Angelani, G Ruocco, Phase Diagram and Complexity of Mode-Locked Lasers: From Order to Disorder,  Physical Review Letters 102, 083901 (2009) Doi:10.1103/PhysRevLett.102.083901 .

Patents

Project

Statistical mechanics of disordered granular laser systems: theory and experiment,” funded by the Italian Ministry of Research (MIUR) program futuro in ricerca. (2010-2015),

NETADIS: Networks across disciplines, FP7-PEOPLE-2011-ITN Project (2011-2015).

Latest News

DIAGNOSTICS OF BRAIN DISEASES VIA STEM CELLS

 01 luglio 2019 - ore 14:15

 

Cnr Nanotec Lecce

 

Realizzato nell'ambito delle attività del progetto "TecnoMed Puglia - Tecnopolo per la medicina di precisione", il meeting è dedicato allo studio delle malattie neurodegenerative: dai nuovi biomarcatori alle piu recenti modellizzazioni, per una migliore comprensione dei meccanismi di base e quindi per lo sviluppo di terapie sempre più ritagliate sul singolo paziente.

EIT RawMaterials Roadshow

21 giugno 2019 ore 09:00 – 15:00

   

Lecce, Aula Fermi Edificio Aldo Romano, Campus Ekotecne, Via Lecce-Monteroni

   

Farà tappa a Lecce il prossimo 21 giugno, presso l’Aula Fermi dell’edificio IBIL all’interno del Campus Ecotekne, l’EIT RawMaterials, la piattaforma per il sostegno all’innovazione finanziata dall’Istituto Europeo di Innovazione e Tecnologia (EIT).

   

L’EIT ha creato le cosiddette KIC – Knowledge Innovation Community, comunità che mirano alla promozione dell’innovazione e della formazione in Europa in settori cruciali, sostenendo l’imprenditorialità e favorendo il passaggio di nuove idee dalla fase di incubazione al mercato.

 

La EIT RawMaterials si impegna ad affrontare la sfida globale dell’approvvigionamento delle materie prime in Europa attraverso programmi e progetti che mirano allo sviluppo di tecnologia nell’intera catena di valore delle materie prime: dall’esplorazione delle risorse, all’industria mineraria, dai processi metallurgici alla sostituzione delle materie prime critiche o tossiche, dal riciclo dei materiali dei prodotti a fine vita sino alla progettazione di prodotti per l’economia circolare. Nell’ambito dei programmi di sviluppo a livello regionale, la EIT RawMaterials ha creato un Hub nella Regione Puglia coordinato da ENEA, al fine di incrementare il coinvolgimento degli ecosistemi locali nelle attività della KIC e del suo partenariato.

 

Il MedinHub avrà inoltre l’obiettivo di raggiungere nuove organizzazioni e promuovere la partecipazione delle industrie e delle PMI più innovative, nonché il coinvolgimento delle prestigiose università e centri di ricerca dell’area.

 

Link per la registrazione:

https://www.lyyti.in/EIT_RawMaterials_Roadshow__Lecce_9500

NanoInnovation 2019

Il Cnr Nanotec è tra i protagonisti di “NanoInnovation 2019", la manifestazione organizzata dall’Associazione italiana per la ricerca industriale (Airi) e dall’Associazione Nanoitaly, ospitata a Roma dall’11 al 14 giugno. Rivolta a ricercatori, imprenditori, industrie, enti di ricerca, NanoInnovation 2019 si propone come la più importante conferenza sulle nanotecnologie e le tecnologie abilitanti in Italia.

 

Il programma dettagliato dell’evento è disponibile al linkhttp://www.nanoinnovation2019.eu/

Tra i partecipanti del Cnr Nanotec:

- Clara Guido, “Non-viral gene delivery using polymeric NPs”;

- LucaLEUZZI, “Overview del progetto ATOM”;

- AlessiaCEDOLA, “La tomografia X e le sue applicazione: dai beni culturali all'industria elettronica”;

- FrancescoMATTEUCCI, “Nanodispositivi per il fotovoltaico integrato”;

- Giuseppe Valerio Bianco, “Chemical strategies to improve CVD graphene’s functionalities in technological applications”