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Sondes actives à base d'un nanocristal semiconducteur unique pour l'optique en champ proche: concept et réalisation

Abstract : The probe commonly used in aperture NSOM consists of a sub-wavelength aperture at the apex of a metal coated sharp dielectric tip, allowing to reach an optical resolution of the order of the aperture size (50 nm). A promising concept consists in replacing the aperture by a subwavelength sized active medium as small as one single molecule or semiconductor nanoparticle. In this scheme, the active probe offers the possibility to obtain a very high resolution defined by the size of the active nano-object. We have developed a method to realize active optical tips for use in near-field optics with the goal of making photostable light nanosources working at room temperature and potentially able to offer optical resolution in the 10 nm range. A metal-coated optical tip is covered with a thin PMMA layer stained with CdSe nanocrystals or nanorods at low density. For this purpose, specially designed optical tips have been prepared using chemical etching and subsequent aluminium coating of optical fibres. They have a free optical aperture at the apex in the 200 nm range. The time-evolution of the spectral signature of the active tips together with temporal analysis of their emission rate in a photon-counting mode clearly demonstrate that a very small number of nanoparticles - possibly down to only one – are active at the tip apex for suitable CdSe dilution rates. The spectral and temporal behaviour of the active tips has been confirmed by studying the emission of single nanonanoparticle dispersed in thin PMMA films using a home-made confocal microscope. NSOM imaging of test surfaces using these active tips are in progress.
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https://tel.archives-ouvertes.fr/tel-00009221
Contributor : Nicolas Chevalier <>
Submitted on : Tuesday, May 10, 2005 - 10:41:31 AM
Last modification on : Tuesday, May 26, 2020 - 11:46:03 AM
Long-term archiving on: : Friday, September 14, 2012 - 1:00:11 PM

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  • HAL Id : tel-00009221, version 1

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Nicolas Chevalier. Sondes actives à base d'un nanocristal semiconducteur unique pour l'optique en champ proche: concept et réalisation. Physique [physics]. Université Joseph-Fourier - Grenoble I, 2005. Français. ⟨tel-00009221⟩

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