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Nucera A, Grillo R, Rizzuto C, Barberi RC, Castriota M, Bürgi T, Caputo R, Palermo G. Effect of the Combination of Gold Nanoparticles and Polyelectrolyte Layers on SERS Measurements. BIOSENSORS 2022; 12:bios12100895. [PMID: 36291032 PMCID: PMC9599540 DOI: 10.3390/bios12100895] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/11/2022] [Accepted: 10/17/2022] [Indexed: 06/02/2023]
Abstract
In this study, polyelectrolyte (PE) layers are deposited on substrates made by glass covered with an array of gold nanoparticles (GNPs). In particular, the samples studied have 0 PE layers (GGPE0), 3 PE layers (GGPE3), 11 PE layers (GGPE11), and 21 PE layers (GGPE21). All samples have been studied by micro-Raman spectroscopy. An acetic acid solution (10% v/v) has been used as a standard solution in order to investigate the SERS effect induced by different numbers of PE layers in each sample. The Surface Enhancement Raman Spectroscopy (SERS) effect correlating to the number of PE layers deposited on the samples has been shown. This effect is explained in terms of an increase in the interaction between the photon of the laser source and the plasmonic band of the GNPs due to a change of the permittivity of the surrounding medium around the GNPs. The trends of the ratios of the intensities of the Raman bands of the acetic acid solution (acetic acid and water molecules) on the band at 1098 cm-1 ascribed to the substrates increase, and the number of PE layers increases.
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Affiliation(s)
- Antonello Nucera
- Department of Physics, University of Calabria, Via Ponte Bucci, Cubo 31C, 87036 Rende, Cosenza, Italy
- CNR-Nanotec, Via Ponte Bucci, Cubo 33C, 87036 Rende, Cosenza, Italy
| | - Rossella Grillo
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - Carmen Rizzuto
- Department of Physics, University of Calabria, Via Ponte Bucci, Cubo 31C, 87036 Rende, Cosenza, Italy
- CNR-Nanotec, Via Ponte Bucci, Cubo 33C, 87036 Rende, Cosenza, Italy
| | - Riccardo Cristoforo Barberi
- Department of Physics, University of Calabria, Via Ponte Bucci, Cubo 31C, 87036 Rende, Cosenza, Italy
- CNR-Nanotec, Via Ponte Bucci, Cubo 33C, 87036 Rende, Cosenza, Italy
| | - Marco Castriota
- Department of Physics, University of Calabria, Via Ponte Bucci, Cubo 31C, 87036 Rende, Cosenza, Italy
- CNR-Nanotec, Via Ponte Bucci, Cubo 33C, 87036 Rende, Cosenza, Italy
| | - Thomas Bürgi
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - Roberto Caputo
- Department of Physics, University of Calabria, Via Ponte Bucci, Cubo 31C, 87036 Rende, Cosenza, Italy
- CNR-Nanotec, Via Ponte Bucci, Cubo 33C, 87036 Rende, Cosenza, Italy
| | - Giovanna Palermo
- Department of Physics, University of Calabria, Via Ponte Bucci, Cubo 31C, 87036 Rende, Cosenza, Italy
- CNR-Nanotec, Via Ponte Bucci, Cubo 33C, 87036 Rende, Cosenza, Italy
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2
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Bošnjaković D, Sebastián N, Drevenšek-Olenik I. Magnetically Tunable Liquid Crystal-Based Optical Diffraction Gratings. Polymers (Basel) 2020; 12:polym12102355. [PMID: 33066481 PMCID: PMC7602225 DOI: 10.3390/polym12102355] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 10/11/2020] [Accepted: 10/12/2020] [Indexed: 11/16/2022] Open
Abstract
We present a theoretical analysis of optical diffractive properties of magnetically tunable optical transmission gratings composed of periodically assembled layers of a polymer and a ferromagnetic liquid crystal (LC). The orientational structure of the LC layers as a function of an applied magnetic field is calculated by minimization of the Landau-de Gennes free energy for ferromagnetic LCs, which is performed numerically and also analytically by using the one-constant approximation and the approximations of the high and the low magnetic fields. Optical diffractive properties of the associated diffraction structure are calculated numerically in the framework of rigorous coupled-wave analysis (RCWA). The presented methodology provides a basis for designing new types of diffractive optical element based on ferromagnetic LCs and simulating their operation governed by the in-plane magnetic field.
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Affiliation(s)
- Dejan Bošnjaković
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia;
- Faculty of Electrical Engineering, Computer Science and Information Technology, Josip Juraj Strossmayer University of Osijek, Kneza Trpimira 2B, 31000 Osijek, Croatia
- Correspondence:
| | - Nerea Sebastián
- J. Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia;
| | - Irena Drevenšek-Olenik
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia;
- J. Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia;
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3
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Gao S, Fleisch M, Rupp RA, Cmok L, Medle-Rupnik P, Mertelj A, Lisjak D, Zhang X, Drevenšek-Olenik I. Magnetically tunable optical diffraction gratings based on a ferromagnetic liquid crystal. OPTICS EXPRESS 2019; 27:8900-8911. [PMID: 31052701 DOI: 10.1364/oe.27.008900] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 02/13/2019] [Indexed: 06/09/2023]
Abstract
Transmission optical diffraction gratings composed of periodic slices of a ferromagnetic liquid crystal and a conventional photoresist polymer are demonstrated. Dependence of diffraction efficiencies of various diffraction orders on an in-plane external magnetic field is investigated. It is shown that diffraction properties can be effectively tuned by magnetic fields as low as a few mT. The tuning mechanism is explained in the framework of a simple empirical model and also by numerical simulations based on the rigorous coupled wave analysis (RCWA). The obtained results provide a proof of principle of operation of magnetically tunable liquid crystalline diffractive optical elements applicable in contactless schemes for control of optical signals.
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Fasanella A, Cosentino K, Beneduci A, Chidichimo G, Cazzanelli E, Barberi R, Castriota M. Thermal structural evolutions of DMPC-water biomimetic systems investigated by Raman Spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1253-1258. [DOI: 10.1016/j.bbamem.2018.02.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 02/20/2018] [Accepted: 02/22/2018] [Indexed: 11/28/2022]
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Dynamic in-situ sensing of fluid-dispersed 2D materials integrated on microfluidic Si chip. Sci Rep 2017; 7:42120. [PMID: 28186118 PMCID: PMC5301493 DOI: 10.1038/srep42120] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/04/2017] [Indexed: 11/08/2022] Open
Abstract
In this work, we propose a novel approach for wafer-scale integration of 2D materials on CMOS photonic chip utilising methods of synthetic chemistry and microfluidics technology. We have successfully demonstrated that this approach can be used for integration of any fluid-dispersed 2D nano-objects on silicon-on-insulator photonics platform. We demonstrate for the first time that the design of an optofluidic waveguide system can be optimised to enable simultaneous in-situ Raman spectroscopy monitoring of 2D dispersed flakes during the device operation. Moreover, for the first time, we have successfully demonstrated the possibility of label-free 2D flake detection via selective enhancement of the Stokes Raman signal at specific wavelengths. We discovered an ultra-high signal sensitivity to the xyz alignment of 2D flakes within the optofluidic waveguide. This in turn enables precise in-situ alignment detection, for the first practicable realisation of 3D photonic microstructure shaping based on 2D-fluid composites and CMOS photonics platform, while also representing a useful technological tool for the control of liquid phase deposition of 2D materials.
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Cacace T, García-García A, Zito G, Tkachenko V, Rusciano G, Geday MA, Otón JM, Marino A, Sasso A. Nematic liquid crystal reorientation around multi-walled carbon nanotubes mapped via Raman microscopy. OPTICS EXPRESS 2016; 24:15954-15964. [PMID: 27410863 DOI: 10.1364/oe.24.015954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We have studied the formation of topological defects in liquid crystal (LC) matrices induced by multiwalled carbon nanotubes (MWCNTs) and external electric fields. The defects are ascribable to a distortion of the LC molecular director in proximity of the MWCNT surface. The system is analyzed macroscopically using spectroscopic variable angle ellipsometry. Concurrently, confocal micro-Raman spectroscopy is used to study the system state at the microscale. This allows to acquire a three-dimensional, spatially-resolved map of the topological defect, determining scale length variations and orientation topography of the LC molecules around the MWCNT.
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Alj D, Caputo R, Umeton C. From Cartesian to polar: a new POLICRYPS geometry for realizing circular optical diffraction gratings. OPTICS LETTERS 2014; 39:6201-6204. [PMID: 25361314 DOI: 10.1364/ol.39.006201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
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 geometry are extended to the polar one by exploiting the spherical aberration produced by simple optical elements. This enables producing the required highly stable polar pattern that allows fabricating a circular optical diffraction grating. Results are promising for their possible application in fields in which a rotational structure of the optical beam is needed.
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Marin L, Popescu MC, Zabulica A, Uji-I H, Fron E. Chitosan as matrix for bio-polymer dispersed liquid crystal systems. Carbohydr Polym 2013; 95:16-24. [PMID: 23618234 DOI: 10.1016/j.carbpol.2013.02.028] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/31/2013] [Accepted: 02/16/2013] [Indexed: 11/28/2022]
Abstract
The obtaining of bio-polymer dispersed liquid crystal (bio-PDLC) systems based on a chitosan polymer matrix is reported here for the first time. The new PDLC composites have been obtained by encapsulation of 4-cyano-4'-pentylbiphenyl (5CB) as low molecular weight liquid crystal into chitosan, and they have been characterized by polarized optical microscopy, differential scanning calorimetry, electron and transmission scanning microscopy, Raman and fluorescence spectroscopy. Submicrometric liquid crystalline droplets with uniform size distribution and density have been obtained for low liquid crystal content into the PDLCs. The droplets have a radial configuration being anchored into chitosan matrix by an interface ordering coupling phenomenon.
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Affiliation(s)
- Luminita Marin
- Petru Poni Institute of Macromolecular Chemistry of Romanian Academy, Iasi, Romania.
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De Sio L, Ferjani S, Strangi G, Umeton C, Bartolino R. Soft Periodic Microstructures Containing Liquid Crystals. J Phys Chem B 2013; 117:1176-85. [DOI: 10.1021/jp311027p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Luciano De Sio
- Department of Physics and Centre
of Excellence for the Study of Innovative Functional Materials, University of Calabria, CNR-IPCF UOS Cosenza, 87036
Arcavacata di Rende (CS), Italy
| | - Sameh Ferjani
- Radiation Oncology, Cleveland Clinic,
9500 Euclid Avenue, Cleveland, Ohio,
44195, United States
| | - Giuseppe Strangi
- Department of Physics and Centre
of Excellence for the Study of Innovative Functional Materials, University of Calabria, CNR-IPCF UOS Cosenza, 87036
Arcavacata di Rende (CS), Italy
- Department
of Physics, Case Western Reserve University, Cleveland, Ohio 44106,
United States
| | - Cesare Umeton
- Department of Physics and Centre
of Excellence for the Study of Innovative Functional Materials, University of Calabria, CNR-IPCF UOS Cosenza, 87036
Arcavacata di Rende (CS), Italy
| | - Roberto Bartolino
- Department of Physics and Centre
of Excellence for the Study of Innovative Functional Materials, University of Calabria, CNR-IPCF UOS Cosenza, 87036
Arcavacata di Rende (CS), Italy
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Heckel JC, Weisman AL, Schneebeli ST, Hall ML, Sherry LJ, Stranahan SM, DuBay KH, Friesner RA, Willets KA. Polarized Raman Spectroscopy of Oligothiophene Crystals To Determine Unit Cell Orientation. J Phys Chem A 2012; 116:6804-16. [DOI: 10.1021/jp304192v] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- John C. Heckel
- Department of Chemistry
and Biochemistry and Center for Nano and Molecular Science, The University of Texas at Austin, Austin, Texas 78712,
United States
| | | | | | | | - Leif J. Sherry
- Department of Chemistry
and Biochemistry and Center for Nano and Molecular Science, The University of Texas at Austin, Austin, Texas 78712,
United States
| | - Sarah M. Stranahan
- Department of Chemistry
and Biochemistry and Center for Nano and Molecular Science, The University of Texas at Austin, Austin, Texas 78712,
United States
| | | | | | - Katherine A. Willets
- Department of Chemistry
and Biochemistry and Center for Nano and Molecular Science, The University of Texas at Austin, Austin, Texas 78712,
United States
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11
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Saito Y, Verma P. Polarization-Controlled Raman Microscopy and Nanoscopy. J Phys Chem Lett 2012; 3:1295-1300. [PMID: 26286773 DOI: 10.1021/jz300213t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Polarization imaging reveals unique characteristics of samples, such as molecular symmetry, orientation, or intermolecular interactions. Polarization techniques extend the ability of conventional spectroscopy to enable the characterization and identification of molecular species. In the early days of spectroscopy, it was considered that a set of polarizers placed in the illumination and the detection paths was enough to enable polarization analysis. However, with the development of new microscope imaging techniques, such as high-resolution microscopy, nonlinear spectroscopic imaging, and near-field microscopy, the inevitable polarization changes caused by external optical components needs to be discussed. In this Perspective, we present some of the hot topics that are specific to high-spatial-resolution microscopy and introduce recent related work in the field. Among the many spectroscopic techniques available, we focus in particular on Raman spectroscopy because Raman tensors are widely used in pure and applied sciences to study the symmetry of matter.
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Affiliation(s)
- Yuika Saito
- Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871 Japan
| | - Prabhat Verma
- Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871 Japan
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12
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De Sio L, Ricciardi L, Serak S, La Deda M, Tabiryan N, Umeton C. Photo-sensitive liquid crystals for optically controlled diffraction gratings. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm16077c] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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