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Theses
Résonances photoniques dans les réseaux métalliques : théorie et application à la photodétection ultrarapide
Résonances photoniques dans les réseaux métalliques : théorie et application à la photodétection ultrarapide
Abstract : Due to surface plasmon resonances, metallic nanostructures are able to focus and to control light on dimensions very small compared to wavelength. During this thesis, the case of transmission metallic gratings have been studied.
Based on a modal method and an S-matrix formalism, an original calculation of complex dispersion curves of metallic gratings have been implemented. The calculation of both the complex photonic band structures and of the spatial distribution of electromagnetic field intensity have allowed a precise description of horizontal and vertical surface resonances. Excitation conditions together with radiative and non-radiative lifetimes have been determined. Their properties of confinement and transmission of light through narrow slits offer new possibilities in optoelectronic.
Two metal-semiconductor-metal structures for ultrafast photodetection are proposed. The confinement of light absorption allows to redifined the usual trade-off between speed and efficiency. In the first structure, metal/semiconductor grating, the light is absorbed between electrodes. In the second structure
the absorption is provided by a fine layer under the electrodes. Both photodetectors, whose inter-electrode spacing is about 100 nm, have been fabricated on GaAs substrates. The good agreement of reflectivity and photocurrent measurements with theory have validated this approach, which could be applied to telecommunication wavelengths.
Cut-off frequencies of several hundreds of GHz could be achieved, with theoretical efficiencies of 75 % for both light polarizations. These results open a new way for ultrafast photodetection.
Based on a modal method and an S-matrix formalism, an original calculation of complex dispersion curves of metallic gratings have been implemented. The calculation of both the complex photonic band structures and of the spatial distribution of electromagnetic field intensity have allowed a precise description of horizontal and vertical surface resonances. Excitation conditions together with radiative and non-radiative lifetimes have been determined. Their properties of confinement and transmission of light through narrow slits offer new possibilities in optoelectronic.
Two metal-semiconductor-metal structures for ultrafast photodetection are proposed. The confinement of light absorption allows to redifined the usual trade-off between speed and efficiency. In the first structure, metal/semiconductor grating, the light is absorbed between electrodes. In the second structure
the absorption is provided by a fine layer under the electrodes. Both photodetectors, whose inter-electrode spacing is about 100 nm, have been fabricated on GaAs substrates. The good agreement of reflectivity and photocurrent measurements with theory have validated this approach, which could be applied to telecommunication wavelengths.
Cut-off frequencies of several hundreds of GHz could be achieved, with theoretical efficiencies of 75 % for both light polarizations. These results open a new way for ultrafast photodetection.
Cited literature [49 references]
https://tel.archives-ouvertes.fr/tel-00142103
Contributor : Stéphane Collin <>
Submitted on : Tuesday, April 17, 2007 - 2:08:13 PM
Last modification on : Sunday, January 3, 2021 - 10:08:02 PM
Long-term archiving on: : Tuesday, April 6, 2010 - 10:51:01 PM
Contributor : Stéphane Collin <>
Submitted on : Tuesday, April 17, 2007 - 2:08:13 PM
Last modification on : Sunday, January 3, 2021 - 10:08:02 PM
Long-term archiving on: : Tuesday, April 6, 2010 - 10:51:01 PM