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Niek van Hulst

ICFO – the Institute of Photonic Sciences, Castelldefels, Barcelona ICREA – Institució Catalana de Recerca i Estudis Avançats, Barcelona

Friday, November 28th, 2014 at 11:30:00 AM  

Conference Room Querzoli LENS

Enrico Fermi Colloquium

Published on-line at 11:47:15 AM on Tuesday, November 18th, 2014

“Antennas for Light: Femtosecond Control on the Nanoscale

Antennas for light can be found both at the molecular scale in natural photosynthetic complexes and at the wavelength scale in the form of engineered plasmonic

Antennas for light can be found both at the molecular scale in natural photosynthetic complexes and at the wavelength scale in the form of engineered plasmonic nanoantennas.

The natural antenna systems are efficient in capturing the light and remarkably quantum coherence plays a role in the transfer of the photon energy. Addressing these photosynthetic complexes is quite challenging as the energy transfer occurs on fs time scale over nanometric distances. In this presentation I will focus on the control of excitation, transfer and emission dynamics of molecular antenna complexes, both in space and time, by resonant optical nanoantennas and phase shaped fs pulses.

For spatial control, we scan resonant optical antennas which have local hotspots of 25-40 nm in size. The nanoantenna provides full command over rates, quantum efficiency, polarization, symmetry and even multipole parity of the emission. Exploiting resonant antenna designs the emission can be enhanced up to 1000 times and steered into a narrow forward angular cone.

For temporal control, we exploit phase shaped fs pulses to drive resonant antennas and single quantum systems to dynamically control both their fs response and nanoscale fields. Interestingly when applied to single photosynthetic antenna complexes we find surprisingly long coherent energy transfer times, even at room temperature.

In conclusion, with this presentation I hope to provide insight on the advances and potential of modern photonics at the cross-roads between nm and fs scales.

For further informations, please contact Francesco Saverio Pavone.