Cesare Paolo Umeton

Cesare Paolo Umeton
Università della Calabria | Università della Calabria · Department of Physics

About

211
Publications
16,966
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3,686
Citations
Citations since 2016
23 Research Items
1142 Citations
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150

Publications

Publications (211)
Article
Full-text available
The coupling of gold nanoantennas (AuNAs) in the arrangement of monomers in bidimensional gratings is investigated both experimentally and numerically. The influence of edge diffraction, corresponding to the grazing propagation of specific diffracted orders, and the dependence of grating parameters on lattice plasmon modes are studied. It is shown...
Data
Luciano De Sio and co-workers demonstrate the extraordinary versatility of gold nanoparticles as nano-sources of heating. From tunable optical components to advanced medical applications, thermoplasmonics represents a far-sighted and multidisciplinary research field to realize innovative, light-driven applications. What’s more, thermoplasmonics can...
Article
Full-text available
Thermoplasmonics In article number 2000198, Luciano De Sio and co-workers demonstrate the extraordinary versatility of gold nanoparticles as nano-sources of heating. From tunable optical components to advanced medical applications, thermoplasmonics represents a far-sighted and multidisciplinary research field to realize innovative, light-driven app...
Article
Full-text available
We experimentally demonstrate that the plasmonic heat delivered by a single layer of homogeneously distributed gold nanoparticles (AuNPs), immobilized on a glass substrate, can be optically tuned by taking advantage of the properties of an organic layer based on azobenzene and nematic liquid crystal (NLC) molecules. The effect, which exploits the d...
Article
Full-text available
Thermoplasmonics deals with the generation and manipulation of nanoscale heating associated with noble metallic nanoparticles. To this end, gold nanoparticles (AuNPs) are unique nanomaterials with the intrinsic capability to generate a nanoscale confined light‐triggered thermal effect. This phenomenon is produced under the excitation of a suitable...
Article
Gold nanoparticle arrangements are identified as plasmonic heaters due to the photo-thermal effects originating from the strong plasmonic confinement of light at the nanoscale. The specific design of the nanoparticle arrangement is crucial to optimize the generation of heat and control its flux. Accurate manipulation of the photo-thermal response o...
Article
We investigate the discrete diffraction phenomenon in a Polymer-Liquid Crystal-Polymer Slices (POLICRYPS) overlaying a random distribution of gold nanoparticles (AuNPs, plasmonic elements). We study the propagation of a CW green laser beam through the waveguide structure as a function of beam polarization, laser intensity and sample temperature. It...
Article
Full-text available
Antibiotic resistance refers to when microorganisms survive and grow in the presence of specific antibiotics, a phenomenon mainly related to the indiscriminate widespread use and abuse of antibiotics. In this framework, thanks to the design and fabrication of original functional nanomaterials, nanotechnology offers a powerful weapon against several...
Article
We present a review of polymer-liquid crystal-based devices for optical applications. Starting from a particular fabrication technique, which enables to obtain the POLICRYPS (POlymer LIquid CRYstal Polymer Slices) structure, we illustrate different realizations, along with their working principle and main features and performances. The name POLICRY...
Presentation
Full-text available
My presentation at the Liquid Crystals Conference (CLC2018) held in Jastrzębia Góra (Poland) from 17th to 21st September 2018
Article
Photo-anisotropic properties of a particular command layer for Liquid Crystals (LCs), based on azo-benzene material, are exploited to control the photo-thermal response of a single layer of homogeneously and uniformly distributed Au nanoparticles, immobilised on a glass substrate. Experiments demonstrate that the intrinsic anisotropy of materials c...
Article
The opto-mechanical control of the heat generated by an amorphous arrangement of homogenously distributed gold nanoparticles (AuNPs), excited by an external laser source, is investigated. Application of a macroscopic mechanical strain to the biocompatible elastomeric tape supporting the particles leads to a nanoscale modification of their mutual in...
Data
This is the supplementary information (ESI) for our paper recently published on Nanoscale reporting about Flexible thermo-plasmonics
Presentation
This presentation reports our result about a novel way to induce localized thermal response by exciting a system of plasmonic units supported by a flexible polymeric substrate (PDMS). A modification of local temperature is produced by applying a strain on the substrate. On this way, the plasmonic units modify their inter-distance and get coupled ge...
Article
Thermo-sensitive liquid crystals may result, for some aspects, good host materials for plasmonic nanoparticles. In particular they are suitable to study and measure the temperature variations produced by photo-induced plasmonic joule effect in the metallic nanoparticles. Combining the properties of liquid crystals and metallic nanoparticles, allows...
Chapter
We have investigated and characterized the unique properties of a liquid crystalline DNA in terms of template and spontaneous-assisted organization by exploiting both top-down and bottom-up approaches. The chemical and physical properties of a passive polymeric template are used to assist the long-range order of a long and short DNA, trapped within...
Article
Controlling light propagation at the nanoscale is a fascinating opportunity offered by modern photonics, more than a challenge to face off. This study is aimed at investigating a particular kind of nanocomposite and reconfigurable optical metamaterials that can be exploited for the realization of a new class of switchable photonic devices, represen...
Article
The use of biomaterials as optical components has recently attracted attention because of their ease of functionalization and fabrication, along with their potential use when integrated with biological materials. We present here an observation of the optical properties of a silk-azobenzene material (Azosilk) and demonstrate the operation of an Azos...
Article
Nematic liquid crystals (NLCs) have proved to be good surrounding materials to investigate variations of physical properties produced by plasmonic resonance in metallic nanoparticles (NPs). In this framework, availability of a simple and reliable tool enabling a complete analysis of dispersion in wavelength and temperature of the refractive index o...
Article
The photo-induced heating from a layer of uniformly distributed gold nanoparticles has been characterized to investigate the impact of a direct interaction of the metallic nanostructures with a drop of E7 nematic liquid crystal. A double effect is obtained: an increase of the photo-induced heating due to a change in the refractive index of the medi...
Article
Full-text available
Policryps structures of photo-curable adhesive NOA61 and nematic liquid crystal mixture E7 have been created inside selected microchannels of photonic crystal fibers (PCF). The PCF was selectively infiltrated with the photopolymer-liquid crystal mixture for the writing of a holographic tunable grating inside specific holes of the photonic fiber. A...
Article
We demonstrate and characterize an optical control of the plasmonic heat delivered by a monolayer substrate of gold nanoparticles, obtained by modulating the effective refractive index of the neighboring dielectric medium. The effect, which exploits the dependence of the nematic liquid crystal (NLC) refractive index on the molecular director orient...
Conference Paper
We report on photo-thermal effects observed in gold nanoparticles (GNPs) dispersed in Nematic Liquid Crystals (NLCs). Under a suitable optical radiation, GNPs exhibit a strong light absorption/scattering; the effect depends on the refractive index of the medium surrounding the nanoparticles, which can be electrically or optically tuned. In this way,...
Article
Full-text available
Local shaping of the polarization state of a light beam is appealing for a number of applications. This can be achieved by employing devices containing birefringent materials. In this article, we present one such device that permits one to convert a uniformly circularly polarized beam into a cylindrical vector beam (CVB). This device has been fabri...
Article
We report on the realization and characterization of electro-responsive and pressure sensitive polydimethylsiloxane (PDMS) conductive photonic structures combined with the reconfigurable properties of short pitch cholesteric liquid crystals (aligned in Grandjean configuration). By combining ion-implantation process and surface chemistry functionali...
Conference Paper
Full-text available
The infiltration of photonic crystal fibers (PCF) with liquid crystals (LC) has greatly evolved since the first infiltration experiments. The combination of the passive properties of PCFs and the active optical properties of LCs has resulted in a new kind of versatile devices, the photonic liquid crystal fibers (PLCF). PLCFs have been developed and...
Chapter
Liquid Crystals (LCs), combining optical nonlinearity and self-organizing properties with fluidity and being responsive to a wide variety of stimuli, have reached a key point in their development for photonic applications, for the realization of devices that can be dynamically reconfigurable, widely tunable and ultra-fast controlled. In this chapte...
Article
Full-text available
We have carried out an experiment on a flexible polymeric substrate, coated with a monolayer of gold nanoparticles, which demonstrates how the combined effect of nanoparticle growth and stretching influences the average normalized gap between particles, thus modifying the extinction spectra of the sample. The study paves the way for the realization...
Chapter
Full-text available
In this chapter, the mechanism of plasmonic coupling of the nearfields that takes place when nanostructures are very close to each other is described. After a theoretical introduction illustrating the main physical principles governing plasmonic coupling, several experimental systems are considered. Interestingly, experimental results show that bot...
Article
The last years have seen a growing interest in the ability of metallic nanoparticles (MNPs) to control temperature at the nanoscale. Under a suitable optical radiation, MNPs feature an enhanced light absorption/scattering, thus turning into an ideal nano-source of heat, remotely controllable by means of light. In this framework, we report our recen...
Article
Localized plasmon resonance (LPR) of noble Metal Nanoparticles (MNPs) opens up a new horizon for nanoscale materials able to convert light into heat, since the strong electric field generated around the MNPs can transform them into original heat nanosources. Thus, investigation of the heat transport mechanism, from the heated MNPs to their surround...
Article
A liquid crystalline, negatively charged, whole-genome DNA is exploited to organize positively charged gold nanorods (GNRs) by means of electrostatic interaction. A mesoscopic alignment of the composite system along a preferred direction is obtained by casting a droplet of the DNA-nanorods solution onto an untreated glass substrate. Gel electrophor...
Chapter
We present a model for the photoinduced formation of composite materials by means of an inhomogeneous curing pattern. The model assumes that redistribution of molecules is due to mass diffusion and incorporates a realistic kinetic description of polymerization processes. Numerical simulations predict two different kinds of structure that have alrea...
Chapter
The use of a nonstandard photocuring technique can produce noticeably improved results: POLICRYPS optimally verifies this condition. Originally being invented as a tunable diffractive structure, POLICRYPS has rapidly attracted much attention for its excellent morphology and related peculiar features. Low light scattering, low switching voltages and...
Article
Full-text available
We report on the realization of a liquid crystal (LC)-based optical diffraction grating showing a polar symmetry of the director alignment. This has been obtained as a natural evolution of the POLICRYPS technique, which enables the realization of highly efficient, switchable, planar diffraction gratings. Performances exhibited in the Cartesian geom...
Article
Full-text available
A simple method is presented to control and trigger the coupling between plasmonic particles using both a growing process of gold nanoparticles (GNPs) and a mechanical strain applied to the elastomeric template where these GNPs are anchored. The large scale samples are prepared by first depositing and then further growing gold nanoparticles on a fl...
Article
A new concept photonic device is realized. It is based on the combination of unusual light control properties of a Thue-Morse nanopatterned photonic quasi-crystal with the extraordinary versatility of “smart” soft matter, represented by azo-liquid crystals. The device, which shows a dramatic polarization selectivity, can be tuned by exploiting eith...
Article
We report on the realization and characterization of a 'free space' diffractive optical filter based on a periodic structure realized in soft composite materials. By combining a high stability optical holographic setup with a light sensitive composite mixture, we have realized a structure made of polymeric slices alternated to pure, well aligned, n...
Article
Gold nanorods embedded in a cholesteric liquid crystal (CLC) enable control of both the “selective reflection” of the CLC and the “plasmonic resonance” of near infrared radiation, thus allowing realization of a bridging between photonics and plasmonics in these materials. These results open up the detection of nanoscale temperature variations, with...
Article
Full-text available
We report an electro-responsive and pressure sensitive device based on conductive polydimethylsiloxane (PDMS) combined with a short pitch Cholesteric Liquid Crystal (CLC). Ion-implantation and surface chemistry in PDMS enable both the induction of conducting properties in this elastomer, as well as a long range organization of the CLC. Sample elect...
Article
Large shifts in the plasmonic resonances of a thin film of gold nanorods (GNRs) are induced through the modulation of the local refractive index of the neighboring dielectric medium. This change is enabled through light-induced surface reorientation of a nematic liquid crystal in contact with a nanometer-thin photoalignment layer coating the GNRs f...
Chapter
Liquid crystals, combining optical non-linearity and self-organizing properties with fluidity, and being responsive to a wide variety of stimuli, have reached a key point in their development for photonic applications, for the realization of devices that could be dynamically reconfigurable, widely tunable and ultra-fast controlled. In this framewor...
Article
We report our recent efforts on the realization and characterization of a conductive polydimethylsiloxane (PDMS) microstructure containing liquid crystals (LC). The sample has been realized by means of a “layer” by “layer” strategy. An indium tin oxide (ITO) layer has been sputtered on PDMS by utilizing thermal evaporation technique; an inter-diffu...
Book
An outstanding route for controlling the diffraction of light by using light is exploited. To this end, we report on the fabrication and characterization of diffraction gratings based on a polymeric microstructure including a light responsive material, which enables an all-optical control of the diffraction of light. The all-optical switching of th...
Chapter
In this chapter we show several possibilities for obtaining active plasmonics in self-organized amorphous materials. The starting point is a brief theoretical description of the physical mechanisms that allow such a tunability. Afterwards, it follows an overview of the up-to-date results obtained in this direction. Several proof-of-concept prototyp...
Article
Full-text available
The acronym POLICRYPS indicates a nano/micro composite structure made of films of well aligned nematic liquid crystal (NLC) alternated to slices of almost pure polymer. Structures are fabricated by curing a homogeneous mixture of mesogenic material, monomer and a curing agent with UV radiation, under suitable physical and geometrical conditions. In...
Article
We have developed a noninvasive, all-optical, holographic technique for permanently aligning liquid crystalline DNA filaments in a microperiodic template realized in soft-composite (polymeric) materials. By combining optical intensity holography with a selective microfluidic etching process, a channelled microstructure has been realized which enabl...
Article
An empty polymeric structure has been realized by combining a high precision level optical holographic setup and a selective microfluidic etching process. The distinctive features of the realized periodic microstructure enabled aligning several kinds of Liquid Crystal (LC) compounds, without the need of any kind of surface chemistry or functionaliz...
Conference Paper
Full-text available
Using self-organizing materials we have demonstrated “active plasmonics” materials/devices in which the plasmonic resonance, optical propagation and diffraction can be finely controlled by means of external perturbations such as electrical or optical field, temperature.
Article
Full-text available
We present a review of a series of nano/micro, soft-matter-based, periodic, composite structures, along with a theoretical model, which explains their main physical and optical features as determined by a suitable choice of the values of given physical and geometrical parameters. The historical development is illustrated by starting from the fabric...
Article
Realization of highly efficient holographic structures can be obtained by combining the POLICRYPS technique and the use of a spatial light mod- ulator. To achieve this result, a new pre-polymer mixture is necessary that is sensitive to visible light and fulfills all requirements of the POLICRYPS technique. In this paper, we report on our efforts to...
Article
A two-fold active control of the plasmonic resonance of randomly distributed gold nanoparticles (GNPs) has been achieved. GNPs have been immobilized on an Indium Tin Oxide (ITO) coated glass substrate and then covered with a liquid crystalline compound. The system has been investigated by means of atomic force and scanning electron microscopy, reve...
Article
Full-text available
In this work we present the first realization and characterization of two-dimensional periodic and aperiodic POLICRYPS (Polymer Liquid Crystal Polymer Slices) structures, obtained by means of a single-beam holographic technique exploiting a high resolution spatial light modulator (SLM). A first investigation shows that the gratings, operating in th...
Article
We report on the fabrication and characterization of a new generation of electro-switchable optofluidic devices based on flexible substrates, combined with the extraordinary properties of reconfigurable soft-materials. A conductive polydimethylsiloxane microstructure has been first sputtered with an Indium Tin Oxide (ITO) layer and then functionali...
Article
We report our recent efforts on the fabrication and characterization of light responsive devices realized in soft composite materials. Periodic microstructures obtained by means of a photolithographic technique and a chemical etching process have been used to micro confine a light responsive liquid crystal stabilized through a self-organization pro...
Article
Gold nanoparticles have been dissolved in a cholesteric liquid crystal and then infiltrated in a micro-periodic polymeric structure. This has been realized by combining a holographic step and a microfluidic etching process. The spectral behavior of the nano-composite soft-structure has been investigated in the UV-Vis range for two different polariz...
Article
Micro-Raman Spectroscopy was used to determine the orientation of the E7 nematic liquid crystal molecules inside the POLICRYPS (POlymer LIquid CRYstal Polymer Slices) holographic gratings. The POLICRYPS grating was analyzed after defining the Raman features of each single component of the system: i.e the random aligned nematic liquid crystal E7 and...
Article
We report on the fabrication and characterization of a tunable filtering effect, observed in a waveguide grating made of alternated strips of photocurable polymer and a mixture of azo-dye doped liquid crystal. The grating is sandwiched between two borosilicate glasses, one of which includes an ion-exchanged channel waveguide, which confines the opt...
Article
Full-text available
Fabrication of samples showing plasmonic properties is a fundamental step towards the realization of devices that can exhibit peculiar electromagnetic properties. In this work we illustrate some fabrication techniques that can reveal useful for the realization of this kind of samples. For what concerns materials, we used polydimethylsiloxane (PDMS)...
Article
We report on distinct dynamic regimes of optically induced redistribution of molecules in a reacting material. The physical system is a mixture of photopolymerizable monomer and nematic liquid crystal with space-time modulated diffusivity. An empirical model is developed which provides an excellent description of all the stages of the experimentall...