Plasmonics

Plasmons are electromagnetic modes associated with the coherent excitation by photons of the free electrons at the interface between a metal and a dielectric material. Their extremely sensitivity to the geometry of the metallic nanostructures allows an extensive tuning of both the spectral properties and associated electromagnetic field distribution by appropriate structural design. In fact, plasmons can be usefully coupled to hybrid organic/inorganic as well as gain materials in order to enhance several optical properties of the nanostructures, e.g. coupling strength, losses mitigation, light to heat conversion on the nanoscale).

Plasmons & plexcitons

Although plasmons have shown unique optical properties, such as extreme light amplification in the near-field, high sensitivity to the surrounding environment and sub-wavelength mode volume, their extremely weak non-linearities put an important limitation to their integration as active components in nano-optical circuits. This limitation can be overcome by combining the plasmonic optical properties with those of organic/inorganic materials, exploiting both the sub-wavelength plasmonic mode volume and the high excitonic nonlinearities. The precise control of such hybrid systems, can open the way for a new generation of utrafast and ultrasmall optical devices. For this reason, in the last years there has been a growing interest in the study of interactions between localized plasmons and nanoscale components, including organic molecules in strong coupling regime. The aim of this line is to develop new insights into the strong coupling between plasmons and organic molecule excitation and exploit their potential applications in photonic quantum communication and quantum information processing. Due to the complex molecular structure, organic molecule exciton-polaritons, PLEXCITON, are in fact still not fully understood. Immagine7With respect to other polariton systems, the effective very small mode volume of localized plasmon is expected to push the coupling strength towards the THz regime with possible room temperature operation.  Strong-coupling regime is then investigated by using different systems in which excitons are coupled to localized plasmons. The experimental techniques used for this study are different ranging from dark field to white field measurements with a confocal system to snom with subwavelength spatial resolution.

Highlights:

We study the effect of the interaction between the localized plasmonic resonance of silver nanodisks and the dipole of an active organic material (cyanine dye). The coupling between the two oscillators is strong enough to enter in the strong exciton-plasmon coupling regime, resulting in the formation of a new quasiparticle, called plexciton, which is able to exploit both plasmonic and excitonic properties.

In particular, we demonstrated that metal oxidation of the silver nanodisks can act, in the regime of small oxidation (shown as aging time in the picture), as a coupling mediator in plasmon-emitter interacting systems resulting in a increasing of the coupling strength with respect to one obtained without oxidation effect.

Gain-Plasmon Dynamics

Main topic here is to study the interplay between gain media and plasmon elements in metamaterials for visible light. The exciton-plasmon dynamics arising by specific coupling configurations has been the core of scientific discussions and experimental studies to explain extraordinary physical processes. In fact, the plasmon-gain coupling has been proposed as a challenging solution to tackle and solve the unavoidable issue of optical losses in metal-based nanostructures with plasmonic resonances at optical frequencies. The fascinating ability of metal nanostructures to localize light at scales much shorter than visible wavelengths is accompanied by enormous ohmic losses, with direct consequences as the remarkable increasing of the extinction cross section of the material. This implies that extraordinary physical properties related to light localization effects at the nanoscale cannot be harnessed to design optical materials because of the strong radiation damping. The idea to bring gain molecules in close proximity to metallo-dielectric nanostructures is based on coherent effects of excitation energy transfer between resonant bands of the two materials. It is well known that relevant modifications of the fluorescence of dye molecules placed in close proximity to metal NPs are due to mutual interactions with NPs surface plasmons, including resonant energy transfer (RET).

Strategies

The research strategies reported here deal with cross-disciplinary approaches that involve design and tailoring of electromagnetic properties, materials preparation, advanced experimental studies and theoretical modeling. Materials functionalization and experimental investigations, like time-resolved and transient absorption spectroscopy, spectrophotometry and spectroscopic ellipsometry, are only a few of the experimental techniques utilized to study how gain-plasmon dynamics can be directed to mitigate optical losses across scales.

Images from ref.4

Thermo-Plasmonics

Plasmonic photothermal therapy (PPTT) is a minimally-invasive oncological treatment strategy in which photonenergy is selectively administered and converted into heat sufficient to induce cellular hyperthermia. To this end, Plasmonic metallic nanoparticles (NPs) are a particular class of nanomaterials which possess the capability to localize light down to the nanoscale by exploiting a phenomenon called Localized Plasmon Resonance (LPR). NPs have been used in therapeutics by triggering drug release or enhancing ablation of diseased tissues, while minimizing damage to healthy tissues. We have performed a Scanning Electron-Microscopy (SEM) characterization of an immortal cell line used in scientific research called “HeLa cell”. The breakthrough idea is based on the possibility to deliver NPs in the tumor site and by exploiting the efficient conversion of Near Infrared (NIR) light to heat opens up a new “drug-free” cancer therapy.

Gene delivery is the process of introducing foreign DNA, RNA into host cells as potential therapeutic strategies for various diseases by means of a nano-vehicle. In particular, the properties of an ideal non-viral vector are: low degradation, target specific cells avoiding immune response in the patient. One of the most promising alternative technologies for gene theraphy is the use of NPs as delivery vehicles. The optical properties of NPs and their biocompatibility provide an efficient tool like non-viral vector for gene therapy. We have combined NPs and a human whole genomic DNA exploiting the possibility to realize applications on the Plasmonic Gene Theraphy (PGT). We have characterized the interaction between NPs and nucleic acids of different length by using analytical techniques, such as electrophoretic mobility assay and scanning electron-microscopy.

Methods

Scanning Electron-Microscopy (SEM); Electrophoretic mobility assay; Zeta-potential mesaures.

Collaborators: Luciano De Sio, Nelson Tabirian –  Beam Engineering for Advanced Measurements Company, Florida , USA; Giulio Caracciolo, Daniela Pozzi – Dipartimento di Medicina Molecolare, Università La Sapienza, Roma; Tiziana Placido, Roberto Comparelli,  Maria Lucia Curri – CNR-IPCF Istituto per i Processi Chimici e Fisici, Sez. Bari, c/o Dip. Chimica, Bari; Angela Agostiano – Università degli Studi di Bari, CNR-IPCF Istituto per i Processi Chimici e Fisici, Bari

Images from ref.8

Facilities & Labs

Photonics Lab @ Lecce

LiCryL @ Rende (CS)

People

Alfredo_PaneAlfredo

Pane

CNR Technician

Antonio_deLucaAntonio

De Luca

Associate Professor

Roberto_bartolinoRoberto

Bartolino

Associate Professor

Giuseppe-StrangiGiuseppe

Strangi

Associate Professor

Ferdinanda_AnnesiFerdinanda

Annesi

CNR Technician

daniele_sanvittoDaniele

Sanvitto

CNR Senior Researcher

milen_degiorgiMilena

De Giorgi

CNR Technologist

paolo_cazzatoPaolo

Cazzato

CNR Techinician

dario_ballariniDario

Ballarini

CNR Researcher

lorenzo_dominiciLorenzo

Dominici

CNR Researcher

Francesco_TodiscoFrancesco

Todisco

Associate PostDoc

BlancaSilva_FernadezBlanca

Silva Fernandez

Associate PhD Student

Viso_UomoAntonio

Fieramosca

Associate PhD Student

Publications

  1. F. Todisco, S. D’Agostino, M. Esposito, A.I. Fernández-Domínguez, M. De Giorgi, D. Ballarini, L. Dominici, I. Tarantini, M. Cuscuná, F. Della Sala, G. Gigli, D. Sanvitto Exciton-Plasmon Coupling Enhancement via Metal Oxidation, ACSNano 9, 9691 (2015), DOI: 10.1021/acsnano.5b04974
  2. M. El Kabbash, A. R. Rashed, K. V. Sreekanth, A. De Luca, M. Infusino and G. Strangi, Plasmon-Exciton Resonant Energy Transfer: Across Scales Hybrid Systems, Journal of Nanomaterials 4819040 (2016) DOI: 10.1155/2016/4819040
  3. A. De Luca, R. Dhama, A. R. Rashed, C. Coutant, S. Ravaine, P. Barois, M. Infusino and G. Strangi, Double strong exciton-plasmon coupling in gold nanoshells infiltrated with fluorophores, Appl. Phys. Lett., 104, 103103, (2014), DOI: 10.1063/1.4868105
  4. A. De Luca, A. Iazzolino, J.-B. Salmon, J. Leng, S. Ravaine, A. N. Grigorenko and G. Strangi, Experimental evidence of exciton-plasmon coupling in densely packed dye doped core-shell nanoparticles obtained via microfluidic technique, J. of Appl. Phys. 116, 104303, (2014), DOI: 10.1063/1.4895061
  5. A. De Sio, F. Annesi, T. Placido, R. Comparelli, V. Bruno, A. Pane, G. Palermo, L. Curri, C. Umeton, R. Bartolino, Templating gold nanorods with liquid crystalline DNA,  J. Opt. 2015, 17, 025001, DOI: 10.1088/2040-8978/17/2/025001
  6. A. De Sio, G. Caracciolo, F. Annesi, T. Placido, D. Pozzi, R. Comparelli, A. Pane, M. L. Curri, A. Agostiano, R. Bartolino, Plasmonics Meets Biology through Optics, Nanomaterials 2015 doi:10.3390/nano50x000x

Project

POLAFLOW: Polariton condensates: from fundamental physics to quantum based devicesStarting Grant ,FP7 – IDEAS – ERC-2012-StG, panel PE2 (2012-2017)

Gain-Plasmon Coupling in Metal-Dielectric Nanostructures: Loss Compensation towards Laser Action, PRIN 2012

Latest News

Loretta del Mercato, si aggiudica l'ERC STARTING GRANT 2017

Loretta del Mercato, si aggiudica  l'ERC STARTING GRANT 2017

uno dei bandi più competitivi a livello europeo.

Lecce, 6 settembre 2017 

Lo European Research Council, che promuove la ricerca di eccellenza in Europa, nei giorni scorsi ha reso noti i nomi dei 406 vincitori della selezione ERC STARTING GRANT 2017, il bando tra i più competitivi a livello internazionale.

Su 3085 progetti presentati, 406 i progetti selezionati a cui sono stati destinati i 605 i milioni di euro di investimento. 48 le nazioni di provenienza dei ricercatori, soltanto 17 gli Italiani che condurranno le loro ricerche nel nostro paese, tra cui Loretta del Mercato, ricercatrice dell'Istituto di Nanotecnologia del Consiglio Nazionale delle Ricerche di Lecce.

Un importante riconoscimento alla ricerca nel settore della medicina di precisione condotta presso il CNR NANOTEC, un indiscusso premio al talento della giovane ricercatrice che, a 38 anni e un contratto a tempo determinato, sarà a capo del progetto "Sensing cell-cell interaction heterogeneity in 3D tumor models: towards precision medicine – INTERCELLMED".

Il progetto, il cui obiettivo è affrontare uno dei problemi più spinosi della ricerca sul cancro, ovvero la difficoltà nel trasformare i risultati delle ricerche scientifiche in applicazioni cliniche per i pazienti e che vedrà coinvolto l'Istituto tumori "Giovanni Paolo II" di Bari, si propone di sviluppare nuovi modelli in vitro 3D di tumore del pancreas, alternativi ai modelli animali, ingegnerizzati con un set di sensori nanotecnologici che consentiranno di monitorare le interazioni delle cellule tumorali con il loro micorambiente, verificare l'appropriatezza delle terapie prima della somministrazione ai pazienti oncologici e quindi prevedere la risposta dei singoli pazienti ad una o più terapie antitumorali.

La realizzazione di queste piattaforme 3D multifunzionali consentirà di superare le evidenti differenze intercorrenti tra "modelli animali" ed esseri umani fornendo dati attendibili ed in tempi più rapidi rispetto ai dati ottenuti tramite lunghi e costosi procedimenti di sperimentazione sugli animali. Le tecnologie e i modelli sviluppati saranno estesi anche ad altre forme di tumori solidi nonché impiegati per studi nell'ambito della ingegneria tissutale e della medicina rigenerativa.

Rassegna stampa e Video

Zeiss Microscopy Technology and Complete Correlative Workflow

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Zeiss Microscopy Technology and Complete Correlative Workflow

Lecce, Italy, 2017 Wednesday July 19th 

CNR NANOTEC @ Lecce, Aula Seminari – pal. G, Piano Terra

Program - PDF

Zeiss, as microscopy technology leader, provides the unique complete imaging solution ranging from light, confocal, electron, ion and Xray modalities with a complete and straightforward correlative workflow. An overview of different technologies will be presented with a special focus on X-Rray microscopy.

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MCS 2017

International Workshop on Micropropulsion and CubeSats

Bari, Italy, 26 - 27 June 2017

Program - MSC2017

This narrow-field, invited-only meeting is the first attempt to bring together the Materials and Micropropulsion communities with a view to contribute to the development of the Global Materials and Micropropulsion Roadmap, and set such meetings to a regular basis.