Pierre-Michel Adam

Pierre-Michel Adam
Université de Technologie de Troyes | UTT · Département de Physique, Mécanique, Matériaux et Nanotechnologies (P2MN)

Professor

About

196
Publications
41,370
Reads
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3,536
Citations
Additional affiliations
January 1995 - December 2013
Université de Technologie de Troyes
Position
  • Université de technologie de Troyes
Description
  • Nanospectroscopy and plasmonics projects

Publications

Publications (196)
Article
Full-text available
Nonresonant surface enhanced Raman scattering by optical phonons of ZnO nanocrystals on and beneath silver and gold island films is reported. For both configurations comparable SERS efficiency is observed, proving their potential utility. Variations in peak intensities can be attributed to difference in the morphology of island films on and beneath...
Article
A strong interest exists in developing Surface-Enhanced Raman Spectroscopy (SERS) substrates that uniformly enhance Raman signals of chemical and biological molecules over large scales while reaching the detection limit of trace concentrations. Even though the resonant excitation of localized surface plasmons of single or assembled metallic nanopar...
Article
Full-text available
Metal-insulator-metal systems exhibit a rich underlying physics leading to a high degree of tunability of their spectral properties. We performed a systematic study on a metal-insulator-nanostructured metal system with a thin 6 nm dielectric spacer and showed how the nanoparticle sizes and excitation conditions lead to the tunability and coupling/d...
Article
Full-text available
The fluorescence of photosystem I (PSI) trimers in proximity to bimetallic plasmonic nanostructures have been explored by single-molecule spectroscopy (SMS) at cryogenic temperature (1.6 K). PSI serves as a model for biological multichromophore-coupled systems with high potential for biotechnological applications. Plasmonic nanostructures are fabri...
Article
The present study compares the near-field and far-field sensitivities of localized surface plasmon resonance (LSPR) sensors. To put into evidence the difference between far-field and near-field sensors, optical extinction measurements have been performed on gold nanoparticle gratings coated with dielectric superstrates of varying thicknesses. The p...
Article
A non-destructive technique for the characterization of the doped regions inside wide bandgap (WBG) semiconductor structures of power devices is presented. It consists in local measurements of the surface potential by Kelvin Probe Force Microscopy (KPFM) coupled to micro-Raman spectroscopy. The combined experiments allow to visualize the space char...
Article
In order to selectively analyze active thin layers close to surface in power devices structures, Raman scattering is necessary with UV excitation. However, the Raman spectra of GaN are usually affected by the direct bandgap photoluminescence of the material, which interferes with the Raman measurements and decreases the quality and resolution of th...
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...
Article
Confocal optical microscopy and tip-enhanced optical microscopy are applied to characterize the defect distributions in CVD-grown WS2 monolayer triangles qualitatively and quantitatively. The presence of defects in individual monolayer WS2 triangles is revealed with diffraction-limited spatial resolution in their photoluminescence (PL) images, from...
Article
Hypericin tautomerization that involves the migration of the labile protons is believed to be the primary photophysical process relevant to its light-activated antiviral activity. Despite the difficulty to isolate individual tautomers, it can be directly observed in single-molecule experiments. We show that the tautomerization of single hypericin m...
Preprint
Full-text available
The metallic nanocylinder is one of the most studied simple plasmonic nanostructures. Due to its internal symmetry, it can sustain different modes, but the majority of the studies focus on the horizontal dipolar resonance. Studying the whole variety of the excited modes in an individual nanocylinder is crucial to the development of further applicat...
Preprint
Full-text available
The plasmon resonances (modes) of a metal nanostructure can be defined as a dipole, a quadrupole, or high-order modes depending on the surface charge distribution induced by the incident field. In a non-symmetrical environment or clusters, the modes can hybridize and exhibit different behavior and properties. In this work, we study experimentally a...
Article
Full-text available
Intense electromagnetic (EM) hot-spots arising at the junctions or gaps in plasmonic nanoparticle assemblies can drive ultrahigh sensitivity in molecular detection by surface-enhanced spectroscopies. Harnessing this potential however requires access to the confined physical space at the EM hot-spots, which is a challenge for larger analytes such as...
Article
Full-text available
Hypericin has large potential in modern medicine and exhibits fascinating structural dynamics, such as multiple conformations and tautomerization. However, it is difficult to study individual conformers/tautomers, as they cannot be isolated due to the similarity of their chemical and physical properties. An approach to overcome this difficulty is t...
Article
Full-text available
Nanoplasmonic sensors based on surface-enhanced spectroscopies carry profound promise toward ultrasensitive detection of biomolecular analytes within miniaturized measurement footprints. High sensitivity in these sensors is achieved by intense electromagnetic (EM) enhancements at hot spots and colocalization of analytes with such hot spots. However...
Article
Full-text available
A single metallic nanodisk is the simplest plasmonic nanostructure, but it is robust enough to generate a Fano resonance in the forward and backward scattering spectra by the increment of nanodisk height in the symmetric and asymmetric dielectric environment. Thanks to the phase retardation effect, the non-uniform distribution of electric field alo...
Article
Full-text available
High sensitivity in plasmon-enhanced spectroscopies results not only from high electromagnetic (EM) field enhancements at the vicinity of nanostructured metal surfaces but also the ability to leverage on these enhancements via analyte colocalization with the EM hot spots. However, promising configurations for EM hot spots such as metal nanogaps are...
Article
Avalanche multiphoton photoluminescence (AMPL) is observed from coupled Au–Al nanoantennas under intense laser pumping, which shows more than one order of magnitude emission intensity enhancement and distinct spectral features compared with ordinary metallic photoluminescence. The experiments are conducted by altering the incident laser intensity a...
Article
Electromagnetic hot-spots at ultranarrow plasmonic nanogaps carry immense potential to drive detection limits down to few molecules in sensors based on surface-enhanced Raman or fluorescence spectroscopies. However, leveraging the EM hot-spots requires access to the gaps, which in turn depends on the size of the analyte in relation to gap distances...
Article
Tautomerization is a fundamental chemical reaction which involves the relocation of a proton in the reactants. Studying the optical properties of tautomeric species is challenging because of ensemble averaging. Many molecules, such as porphines, porphycenes, or phenanthroperylene quinones, exhibit a reorientation of the transition dipole moment (TD...
Article
The plasmon resonances (modes) of a metal nanostructure can be defined as a dipole, a quadrupole, or high-order modes depending on the surface charge distribution induced by the incident field. In a nonsymmetrical environment or clusters, the modes can hybridize and exhibit different behavior and properties. In this work, we study experimentally an...
Preprint
Full-text available
Electromagnetic hot-spots at ultra-narrow plasmonic nanogaps carry immense potential to drive detection limits down to few molecules in sensors based on surface enhanced Raman or Fluorescence spectroscopies. However, leveraging the EM hot-spots requires access to the gaps, which in turn depends on the size of the analyte in relation to gap distance...
Article
We investigate the electrical and thermal conductivities of the two-dimensional electron gas confined in the quantum well formed at the heterojunction between a thin GaN layer and an AlN layer strained by an AlxGa1-xN capping layer in the temperature range from 10 to 360 K. The experimental protocol developed to deduce from calorimetric and Hall-ef...
Preprint
Full-text available
Tautomerization is a fast chemical reaction where structures of the reactants differ only in the position of a proton and a double bond. Tautomerization often occurs in natural substances and is a fundamental process in organic- and biochemistry. However, studying the optical properties of tautomeric species is challenging due to ensemble averaging...
Article
Full-text available
Long-range interaction in regular metallic nanostructure arrays can provide the possibility to manipulate their optical properties, governed by the excitation of localized surface plasmon (LSP) resonances. When assembling the nanoparticles in an array, interactions between nanoparticles can result in a strong electromagnetic coupling for specific g...
Article
To mimic the optical influence of disorder in condensed matter, the effect of uniform disorder on the plasmonic resonances in the near ultraviolet and visible region are investigated numerically and experimentally on aluminum (Al) nanoparticles array. Resorting to the analogue of plasmonic periodic array to crystal on the sharp optical spectrum and...
Conference Paper
Full-text available
The experiments showed the strong dependence of forward and backward scattering of light in the visible region of the spectrum by silicon nanoparticles on the method of their preparation. Silicon nanoparticles are created in two ways: by laser ablation and by the action of a relativistic electron beam. The backscattering spectra from the obtained s...
Article
We present measurements of significant thermal diffusivity by surface electromagnetic waves of an ultra-thin polar and amorphous dielectric film deposited on silicon (Si). We used a photothermal-beam-deflection technique with a modulated mid-infrared heating source to excite and launch surface electromagnetic waves onto the surface of an amorphous...
Article
Full-text available
Multi-resonant plasmonic simple geometries like nanocylinders and nanorods are highly interesting for two-photon photoluminescence and second harmonic generation applications, due to their easy fabrication and reproducibility in comparison with complex multi-resonant systems like dimers or nanoclusters. We demonstrate experimentally that by using a...
Article
Improved performance in flexible organic light-emitting diodes (OLEDs) is demonstrated by using a hybrid nanostructured plasmonic electrode consisting of silver nanowires (AgNWs) decorated with silver nanoparticles (AgNPs) and covered by exfoliated graphene sheets. Such all-solution processed electrodes show high optical transparency and electrical...
Article
Hypericin is one of the most efficient photosensitizers used in photodynamic tumor therapy (PDT). The reported treatments of this drug reach from antidepressive, antineoplastic, antitumor and antiviral activity. We show that hypericin can be optically detected down to a single molecule at ambient conditions. Hypericin can even be observed inside of...
Article
Full-text available
In this paper, we aim at debating the perspectives for plasmonic strain sensors which have attracted interest for the past five years. In particular, we strive to discuss the choice of strategy to increase the sensitivity, either by developing random or ordered assemblies of metallic nanotsructures.
Preprint
The arrangement of plasmonic nanoparticles in a non-symmetrical environment can feature the far-field and/or near-field interactions depending on the distance between the objects. In this work, we study the hybridization of three intrinsic plasmonic modes (dipolar, quadrupolar and hexapolar modes) sustained by one elliptical aluminium nanocylinder,...
Article
The arrangement of plasmonic nanoparticles in a non-symmetrical environment can feature the far-field and/or near-field interactions depending on the distance between the objects. In this work, we study the hybridization of three intrinsic plasmonic modes (dipolar, quadrupolar and hexapolar modes) sustained by one elliptical aluminum nanocylinder,...
Article
Full-text available
In metal–insulator–metal structures such as Au nanodiscs on an Au film separated by a thin oxide spacer layer, the metal/insulator interfaces can form a Fabry–Perot cavity in which gap surface plasmons are confined. As a result, these cavity plasmon modes show the advantageous properties of strong field enhancement and very narrow resonance line sh...
Article
Second-harmonic generation (SHG) is investigated from three kinds of lithographically fabricated plasmonic systems: Al monomers, Au monomers and Au-Al heterodimers with nanogaps of 20 nm. Spectrally integrated SHG intensities and the linear optical responses are recorded and compared. The results show that for the monomer nanoantennas, the SHG sign...
Article
Full-text available
We evaluate experimentally and theoretically the role of the residual ligands and ambient environment refractive index in the optical response of a single spherical gold nanoparticle on a substrate and demonstrate the changes in the near- and far-field properties of its hybridized modes in the presence of the cetyltrimethylammonium bromide (CTAB) l...
Article
Gold nanocones acting as optical antennas offer an excellent geometry for focusing light near the cone tip, acting as nano-light sources with spot sizes on the order of the tip radius. However only the vertical plasmon mode oscillating in the axial direction can effectively excite the tip, whereas lateral modes oscillating along the cone base creat...
Preprint
Full-text available
Hypericin can be found in nature in Hypericum perforatum (St. John's Wort) and has become subject of intense biochemical research. Studies report of antidepressive, antineoplastic, antitumor and antiviral activity of hypericin. Among the variety of potential applications hypericin can be used as photosensitizer in photodynamic therapy (PDT), where...
Article
Full-text available
Phthalocyanines are frequently used as probing molecules in the field of single-molecule surface-enhanced Raman spectroscopy (SERS) and tip-enhanced Raman spectroscopy (TERS). In this work, we systematically compare the SERS and TERS spectra from a thin cobalt phthalocyanine (CoPc) film that is deposited on a Au film. The contributions from electro...
Article
In this work, we discuss excitation of orthogonal and parallel collective resonances in rectangular arrays of aluminum nanoparticles and switch between them with a change of array dimensions or polarization. We demonstrate that in the case of the substrate, scattered fields from nanoparticles can interact with each other in directions both parallel...
Article
Full-text available
In the context of using portions of a photosynthetic apparatus of green plants and photosynthesizing bacteria in bioinspired photovoltaic systems, we consider possible control of the chlorophyll excited state decay rate using nanoantennas in the form of a single metal and semiconductor nanoparticle. Since chlorophyll luminescence competes with elec...
Article
Full-text available
In this study, stable gold nanoparticles (AuNPs) are fabricated for the first time on commercial ultrafine glass coverslips coated with gold thin layers (2 nm, 4 nm, 6 nm, and 8 nm) at 25 °C and annealed at high temperatures (350 °C, 450 °C, and 550 °C) on a hot plate for different periods of time. Such gold nanostructured coverslips were systemati...
Article
Full-text available
High index dielectric nanoparticles have been proposed for many different applications. However, widespread utilization in practice also requires large-scale production methods for crystalline silicon nanoparticles, with engineered optical properties in a low-cost manner. Here, we demonstrate a facile, low-cost, and large-scale fabrication method o...
Article
Smart materials can significantly alter their mechanical, thermal or electromagnetic properties, in response to external stimuli. They have enabled progress in many areas, including drug delivery, self-healing materials for coating applications, or display technologies. Among them, photochromic molecules are well established in glasses technologies...
Article
Full-text available
Active plasmonics is a key focus for the development of advanced plasmonic applications. By selectively exciting the localized surface plasmon resonance sustained by the short or the long axis of silver nanorods, we demonstrate a polarization-dependent strong coupling between the plasmonic resonance and the excited state of photochromic molecules....
Article
The metallic nanocylinder is one of the most studied simple plasmonic nanostructures. Due to its internal symmetry, it can sustain different modes, but the majority of the studies focus on the horizontal dipolar resonance. Studying the whole variety of the excited modes in an individual nanocylinder is crucial to the development of further applicat...
Article
Full-text available
Interest in graphene has been widely increasing since its discovery in 2004. Research on graphene for plasmonic applications has also boomed due to the high potential of these systems. In this article, we discuss the possible interaction between metallic NPs and graphene monolayer. We show how the contact between metallic NPs and graphene results i...