Source: https://www.institut-langevin.espci.fr/samuel_gresillon?lang=fr
Timestamp: 2019-04-20 06:22:11+00:00

Document:
pour le développement de nouveaux outils de caractérisation optique à petites échelles.
Direct determination of diffusion properties of random media from speckle contrast.
Curry, N., P. Bondareff, M. Leclercq, N. F. Van Hulst, R. Sapienza, S. Gigan, and S. Grésillon.
Optics Letters 36, no. 17 (2011): 3332–3334.
Résumé: We present a simple scheme to determine the diffusion properties of a thin slab of strongly scattering material by measuring the speckle contrast resulting from the transmission of a femtosecond pulse with controlled bandwidth. In contrast with previous methods, our scheme does not require time measurements nor interferometry. It is well adapted to the characterization of samples for pulse shaping, nonlinear excitation through scattering media, and biological imaging. © 2011 Optical Society of America.
Low temperature near-field scanning optical microscopy of IR and THz surface-plasmon quantum cascade lasers.
Moldovan-Doyen, I., A. Babuty, A. Bousseksou, R. Colombelli, S. Grésillon, and Y. De Wilde.
Résumé: We present the first scattering type near-field scanning optical microscope operating at low temperature. This instrument is ideal to study infrared and terahertz QCLs combined with metallic photonic crystal resonators and surface plasmon waveguides. © 2010 Optical Society of America.
Nanoparticle based integrated plasmonic component.
Delahaye, J., S. Grésillon, and E. Fort.
In CLEO/Europe – EQEC 2009 – European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference., 2009.
Narrowing of non linear enhancements in near-field images.
Grésillon, S., L. Williame, E. L. Moal, E. Fort, and A. C. Boccara.
In Proceedings of SPIE – The International Society for Optical Engineering. Vol. 6324., 2006.
Résumé: In our attempt to reveal highly localized field enhancements on random metallic films using near-field scattering probe microscopy we experimentally demonstrated the existence of narrow peaks when using a monochromatic illumination. In order to get a better understanding of the second harmonic generation taking place on such films we have undertaken the same kind of near-field experiments using femtosecond lasers sources with high peak power able to induce the non linear response. These lasers have a spectral bandwidth associated with the pulse duration, which is in the femtosecond range. With such spectral broadening we have observed, as expected, a spatial broadening of the peaks at ω, which spread over distances in the 100-500 nm range. The behavior of the peaks is quite different at 2 ω: they are found to be always very well localized (∼10 nm) despite of the polychromatic nature of the light; moreover there is no clear correlation between the peaks position at ω and those at 2 ω. This observation indicates, as often underlined in non linear processes, that coherent interactions involving a distribution of available frequencies in the lasers spectra take place. These frequencies ωn, coherently induce second harmonic generation as long as ωn + ωm = 2 ω.
Moneron, G., A. Fragola, F. Formanek, L. Williame, A. Dubois, L. Aigouy, Y. de Wilde, S. Grésillon, and C. Boccara. Chapter 9 Scattering probes: From 2-D to 3-D near field imaging. Vol. 1., 2004.
Imaging subwavelength holes in chromium films in scanning near-field optical microscopy. Comparison between experiments and calculation.
Ducourtieux, S., S. Grésillon, J. C. Rivoal, C. Vannier, C. Bainier, D. Courjon, and H. Cory.
EPJ Applied Physics 26, no. 1 (2004): 35–43.
Résumé: Near-field optical signals are imaged in the vicinity of nano-holes using two different near-field optical microscopes. The experimental results are compared with electromagnetic field calculations based on a modal approximation. It turns out that an optical fibre detects the Poynting vector whereas the apertureless tip is sensitive to the field amplitude. © EDP Sciences.
Near-field optical studies of semicontinuous metal films.
Ducourtieux, S., V. A. Podolskiy, S. Grésillon, S. Buil, B. Berini, P. Gadenne, A. C. Boccara, J. C. Rivoal, W. D. Bragg, K. Banerjee et al.
Physical Review B – Condensed Matter and Materials Physics 64, no. 16 (2001): 1654031–16540314.
Résumé: Local field distributions in random metal-dielectric films near a percolation threshold are experimentally studied using scanning near-field optical microscopy (SNOM). The surface-plasmon oscillations in such percolation films are localized in small nanometer-scale areas, “hot spots”, where the local fields are much larger than the field of an incident electromagnetic wave. The spatial positions of the hot spots vary with the wavelength and polarization of the incident beam. Local near-field spectroscopy of the hot spots is performed using our SNOM. It is shown that the resonance quality-factor of hot spots increases from the visible to the infrared. Giant local optical activity associated with chiral plasmon modes has been obtained. The hot spot's large local fields may result in local, frequency and spatially selective photomodification of percolation films.
Experimental observation of percolation-enhanced nonlinear light scattering from semicontinuous metal films.
Breit, M., V. A. Podolskiy, S. Grésillon, G. Von Plessen, J. Feldmann, J. C. Rivoal, P. Gadenne, A. K. Sarychev, and V. M. Shalaev.
Physical Review B – Condensed Matter and Materials Physics 64, no. 12 (2001): 1251061–1251065.
Résumé: Strongly enhanced second-harmonic generation (SHG), which is characterized by a nearly isotropic intensity distribution, is observed for gold-glass films near the percolation threshold. The diffuselike SHG scattering, which can be thought of as nonlinear critical opalescence, is in sharp contrast with highly collimated linear reflection and transmission from these nanostructured semicontinuous metal films. Our observations, which can be explained by giant fluctuations of local nonlinear sources for SHG due to plasmon localization, verify recent predictions of percolation-enhanced nonlinear scattering.
Nanometer scale apertureless near field microscopy.
Grésillon, S., S. Ducourtieux, A. Lahrech, L. Aigouy, J. C. Rivoal, and A. C. Boccara.
Applied Surface Science 164, no. 1-4 (2000): 118–123.
Résumé: It is necessary to use the information contained in the near field to get sub-wavelength details in optical imaging which are not revealed through the far-field image. We have designed and built various setups able to perform near-field measurements in the UV, visible and IR, both in transmission, reflection and dark field with a resolution of 10 nm, independent of the wavelength but related to the tip size. Images revealing local dielectric contrasts, small particle effects, as well as local field enhancements in random structures, are shown. © 2000 Published by Elsevier Science B.V.
Percolation and fractal composites: Optical studies.
Ducourtieux, S., S. Grésillon, A. C. Boccara, J. C. Rivoal, X. Quelin, P. Gadenne, V. P. Drachev, W. D. Bragg, V. P. Safonov, V. A. Podolskiy et al.
Journal of Nonlinear Optical Physics and Materials 9, no. 1 (2000): 105–116.
Résumé: Local field distributions arc studied in random metal-dielectric films near percolation (percolation films) and fractal aggregates of colloidal particles. For both systems, it is shown that optical excitations are localized in small nanometer-scale areas, “hot spots,” where the local fields are much larger than the field of an incident electromagnetic wave. The large local fields result in giant enhancement of various optical phenomena. The surface-enhanced white-light generation and second-harmonic generation have been obtained in percolation films. For fractal aggregates of silver particles, a giant effect of local optical activity has been observed. The effect is due to surface-plasmon excitations localized on chiral-active particle configurations in fractals.
Nanoscale observation of enhanced electromagnetic field.
Grésillon, S., J. - C. Rivoal, P. Gadenne, X. Quélin, V. Shalaev, and A. Sarychev.
Physica Status Solidi (A) Applied Research 175, no. 1 (1999): 337–343.
Résumé: The surface of nanosized discontinuous or rough metal thin films is able to induce Raman scattering enhanced by several orders of magnitude. This effect has been theoretically attributed to the local field distribution at the surface of the films. As for the relevant parameter in phase transitions, the fields experience here huge fluctuations, leading to localized giant peaks so called `hot spots'. Using a Scanning Near-Field Optical Microscope (SNOM) of extremely high lateral resolution (10 nm), we have been able to record the field distribution close to the surface of gold films. We report here the first direct observation of the hot spots with such lateral resolution. Their intensities and spatial distribution are found in good agreement with the theoretical predictions. We also have performed local spectroscopy, which shows up sharp variations at nanometric scale (much smaller than the wavelength).
Experimental observation of localized optical excitations in random metal-dielectric films.
Grésillon, S., L. Aigouy, A. C. Boccara, J. C. Rivoal, X. Quelin, C. Desmarest, P. Gadenne, V. A. Shubin, A. K. Sarychev, and V. M. Shalaev.
Physical Review Letters 82, no. 22 (1999): 4520–4523.
Résumé: The localized optical excitations in random metal-dielectric films were examined by scanning near-field optical microscopy. The patterns of the observed surface plasmon modes localized in hot spots are attributed to Anderson electron localization and are found to agree with theoretical predictions.
Electric field diffraction by a semi-infinite perfectly conducting plane of small thickness: application to near-field microscopy.
Cory, H., A. C. Boccara, J. C. Rivoal, and S. Grésillon.
Microwave and Optical Technology Letters 21, no. 3 (1999): 177–183.
Résumé: A perfectly conducting half plane of finite thickness much smaller than the wavelength of the incident electromagnetic wave is investigated. The geometry of the structure is defined according to a transformation which is a particular case of the Schwarz-Christoffel transformation, representing a step with a slightly concave edge instead of the usual straight one. The solutions of the partial differential equations describing the structure are given for specific ranges of the variables, and the results obtained with this method are compared to those obtained with an independent numerical method for a step with a straight edge. Good agreement is obtained between the two sets of results, except right around the edges of the steps in the two structures, due to the different shapes involved. It is shown that the width of the structure has but a slight influence on the value of the electric field, while the angle of incidence of the incoming wave has a strong influence on this value.
Transmission-mode apertureless near-field microscope: optical and magneto-optical studies.
Grésillon, S., H. Cory, J. C. Rivoal, and A. C. Boccara.
Journal of Optics A: Pure and Applied Optics 1, no. 2 (1999): 178–184.
Résumé: A new near-field optical microscope working in transmission is presented. Lateral optical resolution less than 10 nm is obtained with a pure metallic probe. Polarization images of a metallic step confirmed the good resolution by comparison with an analytical model. We also demonstrate the capability of the microscope to obtain images with polarization effects. The good resolution is used for the observation of small gold aggregates which confirm that this microscope is able to make spectroscopic measurements of the optical effect induced by a nanometric scale particle. The polarization sensibility allows us to measure near-field magneto-optical contrast on a multi-layer sample with magnetic domains. These results are promising for magneto-optical characterization with nanometre resolution.

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