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Presenter: Amirhossein AlizadehKhaledi
Supervisor:

Date: Fri, November 8, 2019
Time: 13:30:00 - 14:30:00
Place: EOW 430

ABSTRACT

Abstract:

Plasmonic has been used to increase the upconversion efficiency of lanthanide-doped nanocrystals.   This can be achieved by using plasmonic resonators at the emission and / or absorption wavelengths of the upconverters.  In this seminar, the interaction of light and upconversion nanocrystals (UCNC) is investigated.  Rectangular apertures on a gold film are fabricated and used to trap and study single UCNCs.  These apertures are finely tuned to find the highest UCNC emission enhancements.  Results show significant up to 400× enhancement along with many other interesting observations for trapped UCNCs.  Finite-difference time-domain (FDTD) simulations show multiple plasmonics resonances at emission and absorption UCNCs wavelengths which can justify the experimental results.  These results could be a path for understanding the interaction of light and UCNC at very subwavelength scales and eases the application of UCNCs in photovoltaics, photocatalysis, single-photon source and bio-imaging.

The single-photon sources are emission sources that can emit a single photon as demanded.  One way to achieve a single-photon source at optical favorite wavelengths like 1550 nm is by using a single lanthanide ion inside a cavity with a huge emission enhancement factor. The plasmonic enhancement for this work was about 400 times and the nanocrystals each contained approximately 2,000 Erbium ions. Considering that we could detect emission for even the case of no plasmonic enhancement, that experiment opened the door for the important next step of detecting single Er ion emitters.