Spatiotemporal Characterization of SPP Pulse Propagation in Two-Dimensional Plasmonic Focusing Devices

ROM 2014-8
Author: M. Bauer / Kiel & M. Aeschlimann / Kaiserslautern
Publication: Nano Lett., 2013, 13 (3), pp 1053–1058
Instrument: FOCUS PEEM

The spatiotemporal evolution of a SPP wave packet with femtosecond duration is experimentally investigated in two different plasmonic focusing structures. A two-dimensional reconstruction of the plasmonic field in space and time is possible by the numerical analysis of interferometric time-resolved photoemission electron microscopy data. We show that the timeintegrated and time-resolved view onto the wave packet dynamics allow one to characterize and compare the capabilities of twodimensional components for use in plasmonic devices operating with ultrafast pulses.

In recent years, ultrafast optical approaches have increasingly been applied to nano-optical problems. ‘Ultrafast nanooptics’ in particular, needs sophisticated methods for a comprehensive characterization of the complex dynamics of localized optical excitations simultaneously in space and time. Femtosecond laser-based PEEM provides such a capability, as has been shown in the past by a number of pioneering studies. With regard to the real-time observation and characterization of plasmonic wave packet motion, this technique, as well as other approaches, were mainly restricted to one-dimensional scenarios in the past. In the present work,

we demonstrated how the interferometric time-resolved PEEM technique, together with proper numerical simulations, can be used to reconstruct and visualize the two-dimensional evolution of ultrashort SPP wave packets in space and time. The analysis presented here provided quantitative insights into details of the group propagation of plasmonic fields in complex structures. In particular, we experimentally demonstrated the two-dimensional propagation and spatiotemporal focusing of sub-15 fs SPP wave packets.

The approach presented here is not only restricted to ITR-PEEM experiments but can also be applied to other experimental techniques where plasmon propagation is probed by the interference with a reference laser field. Prospects of this approach include the analysis of time-resolved data in terms of SPP phase modulation in highly dispersiveplasmonic systems that should give rise to a wave packet broadening during propagating.

The method demonstrated here for time-resolved recording of SPP propagation in complex two-dimensional plasmon-optical assemblies further provides the possibility to analyze the temporal evolution of SPP pulses prepared with defined amplitude and/or phasemodulation by laser pulse-shaping techniques.

Christoph Lemke (1), Christian Schneider(2), Till Leißner(1), Daniela Bayer (2), Jörn W. Radke(1), Alexander Fischer(2), Pascal Melchior(2), Andrey B. Evlyukhin(3), Boris N. Chichkov(3), Carsten Reinhardt (3), Michael Bauer(1), and Martin Aeschlimann(2)

(1) Institute for Experimental and Applied Physics, University of Kiel, Kiel, Germany
(2) Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Kaiserslautern, Germany
(3) Laser Zentrum Hannover e.V., Hannover, Germany