Timothée Toury

Université de Technologie de Troyes | UTT · Laboratoire de Nanotechnologie et d’Instrumentation Optique (LNIO)

Priority substances likely to pollute water can be characterized by mid-infrared spectroscopy based on their specific absorption spectral signature. In this work, the detection of volatile aromatic molecules in the aqueous phase by evanescent-wave spectroscopy has been optimized to improve the detection efficiency of future in situ optical sensors...

We present a new realization of the textbook experiment consisting in single-photon interference based on the pulsed, optically excited photoluminescence of a single colour centre in a diamond nanocrystal. Interferences are created by wavefront-splitting with a Fresnel's biprism and observed by registering the "single-photon clicks" with an intensi...

We report a detailed investigation on the second harmonic generation (SHG) emission from single 150 nm diameter non-centrosymmetric gold nanoparticles. Polarization-resolved analysis together with scanning electron microscopy images shows that these nanostructures exhibit a unique polarization-sensitive SHG that depends strongly on the particle's s...

Gold nanostructures (GNS) were defined that are chemically functionalized by four different diazonium salts: benzene-diazonium-tetrafluoroborate (DS), 4-decyl benzene-diazonium-tetrafluoroborate (DS-C10H21), 4-carboxybenzene-diazonium-tetrafluoroborate (DS-COOH) and 4-(aminoethyl)-benzene-diazonium-tetrafluoroborate (DS-(CH2)2NH2). The effective ch...

The electromagnetic field near the focus of a perfect imaging system is calculated for different multipolar sources that play an important role in the radiation of nanostructures. Those multipoles are the exact and extended multipoles occurring in electrodynamics. The theory of diffraction of vector waves is reviewed rigorously for a dipolar radiat...

Optimum amplification in Surface Enhanced Raman Scattering (SERS) from individual nanoantennas is expected when the excitation is slightly blue-shifted with respect to the Localized Surface Plasmon Resonance (LSPR), so that the LSPR peak falls in the middle between the laser and the Stokes Raman emission. Recent experiments have shown when moving t...

Nanoplasmonics is a growing field of optical condensed matter science dedicated to optical phenomena at the nanoscale level in metal systems1. Extensive research on noble metallic nanoparticles (NPs) has arisen within the last two decades due to their ability to keep the optical energy concentrated in the vicinity of NPs, in particular, the ability...

Gold is one of the most widely used metals for building up plasmonic devices. Although slightly less efficient than silver for producing sharp resonance, its chemical properties make it one of the best choices for designing sensors. Sticking gold on a silicate glass substrate requires an adhesion layer, whose effect has to be taken into account. Tr...

In recent years, nanowires have been proven efficient to enhanced IR absorption of molecules and opened prospects of new ultrasensitive IR sensors. The development of integrated components requires the use of special IR glasses such as chalcogenide or silver halide glasses. In this study, we report the fabrication of a surface enhanced IR absorptio...

The 3-15 μm range is a key region for a large number of applications in diverse areas such as biology and medicine, molecular spectroscopy, ground based and space borne environmental monitoring but also an important issue of instrumentation for astronomy and astrophysics to achieve complex but very reliable instruments. Going to the mid IR region i...

We have developed a new electrochemical etching procedure to fabricate gold tips with sub-50 nm apical radius of curvature with a production yield of 80% and production time lower than 5 min. The technique is based on a two-step self-terminating process in which a gold wire is first quickly (<1 min) pre-etched in an hydrochloric acid (HCl)/ethanol...

Gold nanostructures have very suitable physical properties for plasmonic applications but do not stick on glass substrates. One usually uses a chromium adhesion layer that gives good mechanical adhesion but quench the plasmon. We developed a new adhesion process that permits a covalent bonding between gold and glass thanks to an MPTMS molecular lay...

This paper outlines the design of complex nanostructures with apolar behavior which pave the way to a wider range of plasmon resonance tuning and applications requiring higher enhancement. These new nanostructure families are simply defined by symmetry considerations. An irreducible decomposition of optical response tensor demonstrates that nanopar...

We report spatial and vectorial imaging of local fields' confinement properties in metal nanoparticles with branched shapes, using Second Harmonic Generation (SHG) microscopy. Taking advantage of the coherent nature of this nonlinear process, the technique provides a direct evidence of the coupling between the excitation polarization and both local...

In this study, we demonstrate that any complex nanostructure that belongs to CnCn, with n≥3n≥3, symmetry point group for along at least one dimension displays apolar linear response to light input when the incoming wave vector is parallel to the CnCn axis. Triangle and star shaped gold nanoparticles were designed and fabricated by electron beam lit...

The paper outlines the optimization of plasmonic nanostructures in order to improve their sensing properties such as their sensitivity and their ease of manipulation. The key point in this study is the optimization of the localized surface plasmon resonance (LSPR) properties essential to the sensor characteristics, and more especially for surface-e...

Among the various novel analytical systems, immunosensors based on acoustic waves are of emerging interest because of their good sensitivity, real-time monitoring capability, and experimental simplicity. In this work, piezoelectric immunosensors were constructed for the detection of atrazine through the immobilization of specific monoclonal anti-at...

Ultrasensitive chemical and biochemical sensors are based on nanostructured gold surfaces on glass with good surface-enhanced Raman scattering measurement properties and enough good adhesion properties between gold and glass. In this paper, the scratch test is used in a new way to assess the critical load which takes off dashed gold lines on a glas...

We here emphasize that the Surface Enhanced Raman Scattering (SERS) intensity has to be optimized by choosing the appropriate gold nanoparticles size for two excitation wavelengths: 632.8 and 785 nm. We discuss the role of the position and of the order of the Localized Surface Plasmon Resonance (LSPR) in such optimization for both wavelengths. At 6...

The device has a set of nanometric pads distributed at a surface of a support e.g. object, for forming a homogeneous planar array, where each pad is a non-linear optical diffraction and diffusion pad. Each pad extends remote from the support along an axis. The pads, which are non centro-symmetric, are distributed on the support along different orie...

In the investigation of chemical pollutants, such as PAHs (Polycyclic Aromatic Hydrocarbons) at low concentration in aqueous medium, Surface-Enhanced Raman Scattering (SERS) stands for an alternative to the inherent low cross-section of normal Raman scattering. Indeed, SERS is a very sensitive spectroscopic technique due to the excitation of the su...

In this paper we highlight the accurate spectral detection of bovine serum albumin and ribonuclease-A using a surface-enhanced Raman scattering (SERS) substrate based on gold nanocylinders obtained by electron-beam lithography (EBL). The nanocylinders have diameters from 100 to 180 nm with a gap of 200 nm. We demonstrate that optimizing the size an...

In the investigation of chemical pollutions, such as PAHs (Polycyclic Aromatic Hydrocarbons) at low concentration in aqueous medium, surface‐enhanced Raman scattering (SERS) stands for an alternative to the inherent low cross‐section of normal Raman scattering. Indeed, SERS is a very sensitive spectroscopic technique due to the excitation of the...

We have studied the Surface‐Enhanced Raman Scattering (SERS) of shape controlled metallic nanoparticles: nanocylinders and nanowires, designed through electron beam lithography and lift off techniques. We have notably studied the influence of Localized Surface Plasmon Resonance (LSPR) on the efficiency of SERS. We will demonstrate that the nanowi...

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This study describes the effect of the surrounding medium on the SERS efficiency using nanolithographied substrates on which Polycyclic Aromatic Hydrocarbons are investigated. We will show that the optimum nanocylinder size is shifted to lower diameter by increasing the dielectric constant of the liquid medium. This rule is discussed in terms of Lo...

The sensitivity of infrared (IR) vibration spectroscopy can be enhanced by several orders of magnitude if plasmonic electromagnetic nearfield enhancement is exploited. For maximum enhancement the plasmonic resonance needs to be strong, which cannot be achieved by randomly grown metal island films that on average may show already signal enhancement...

We here emphasize that the surface enhanced Raman scattering (SERS) intensity has to be optimized by choosing the appropriate gold nanoparticles size for two excitation wavelengths; 632.8 and 785 nm. We discuss the role of the position and of the order of the localized surface plasmon resonance (LSPR) in such optimization for both wavelengths. At 6...

An adapted method of optimization of coated metallic nanoparticles is introduced to perform the optimal choice of material and sizes for better scattering or absorption efficiency. This design of nanoshells, involving plasmon resonance, is achieved to maximize the efficiency factors. The presented method is turned to tune the efficiency of nanoshel...

With infrared spectroscopic microscopy using synchrotron radiation, we systematically studied resonant light scattering from electron-beam lithographically produced gold nanowires (nanostripes) with diameters in the 100 nm range and with various lengths below 1 to about 2.5 μm. Similar to electrochemically grown cylindrical wires of high crystallin...

The efficiency of plasmon-resonance-based sensors can be greatly improved with an accurate design of the nano-structures that constitute them. In this work we focus our attention on the design of a particular kind of these nanometric structures that consists of planar multilayered systems. We show the significant influence, on the plasmon resonance...

The efficiency of plasmon-resonance-based sensors can be greatly improved with an accurate design of the nano-structures that constitute them. In this work we focus our attention on the design of a particular kind of these nanometric structures that consists of planar multilayered systems. We show the significant influence, on the plasmon resonance...

Nous présentons une nouvelle réalisation de l'expérience d'interférence à un photon basée sur une source de photons uniques et un interféromètre à division de front d'onde réalisé à l'aide d'un biprisme deFresnel.

The first demonstration, to the best of our knowledge, of electro-optical microscopy is presented and applied to a polymer-based optical device. A confocal transmission microscope with interferometric homodyne detection is implemented to measure Pockels phase shifts with micrometric spatial resolution and an accuracy level down to 4 x 10(-7) rad. T...

We present a new microscopy technique allowing electric field mapping in molecular media with micrometer resolution : electro-optical microscopy. We apply it to polymer devices and local measurements of transmembranar potentials in biomimetic membranes.

Electro-optical microscopy is a micrometric quantitative mapping technique of electrical fields and of electro-optical tensor components in a medium. The set-up is a confocal microscope included in an interferometer with homodyne detection used to record and measure weak phase shifts due to Pockels effect. The sample must be transparent, quadratica...

We present a new realization of the textbook experiment consisting in single-photon interference based on the pulsed, optically excited photoluminescence of a single colour centre in a diamond nanocrystal. Interferences are created by wavefront-splitting with a Fresnel's biprism and observed by registering the “single-photon clicks” with an intensi...

The first off-resonance hyperpolarizabilities (β(0)) of bisubstituted carotenoids are computed and analyzed using a quasiparticle, collective electronic oscillators (CEO) representation. The few oscillators which dominate the response are identified by solving the time dependent Hartree−Fock equations for the reduced single electron density matrix....