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AMO/IQSE SEMINAR SERIES


"THE BEHAVIOR OF LIGHT MATTER INTERACTION AT NANOSCALE"


Dr. Euclydes Marega Junior
Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Brazil Center for Optics and Photonics (CEPOF)

ABSTRACT 

The past few decades saw a huge effort to provide a solution to the problem of controlling the optical properties of optoelectronic and photonic devices. Particularly the discovery of the extraordinary optical transmission of light when crossing a sub-wavelength array of holes fabricated in a thin metallic film due to the coupling of the electromagnetic field with the free electrons in the metal nanostructures generating surface-plasmons polaritons (SPP's). These electromagnetic waves propagate along the surface but are spatially confined in directions perpendicular to it. The confinement is below the focusing diffraction limit by more than a factor of three on the dielectric side and more than a factor ten on the metal side. The range of propagation of the guided surface mode, the SPP is on the order of 50 microns or about 100 wavelengths. This strong transverse confinement and relatively long propagation length give rise to novel light-matter interaction at the nanoscale opening a new area called Plasmonic. The confinement of the electrons in the interface gives rise to strong electromagnetic fields in the surrounding media and may enhance the coupling of the electromagnetic field with, for example, semiconductor quantum dots (QDs). As a result of this coupling, the exciton decay behavior of the QDs is due to a mechanism that also needs to include the decay into SPPs. This mechanism becomes stronger as the distance between the QDs and the metal-dielectric interface become smaller, a result that is expected by the dependence of the coupling constant for dipolar interaction. In this talk, we show results on the dependence of excitons spectra and lifetime confined in InAs/GaAs QDs near a gold metasurface (array of sub-wavelength gold nanostructures). When the InAs QDs are placed near the thin nanostructured metallic film (separated by a GaAs layer), there will be a competition between the radiative decay rate into the light and into SPPs supported by the metallic film, an important step toward the investigation of the basic features of the SPP-exciton interaction. One of the focuses of this work was the study of light to develop novel devices based on photonics. As a result, it was observed a strong coupling of light with SPPs and the possibility of manipulating light below the diffraction limit creating new quantum aspects of light-matter interaction.


Wednesday, July 10, 2019
IQSE Seminar Room, 2:00 PM
(578 MPHY)


Institute for Quantum Science and Engineering
Texas A&M University

Coffee to be served at 2PM

Host: Dr. Alexey Belyanin