Stuttgart 2012 – wissenschaftliches Programm
Q 10.1: Vortrag
Montag, 12. März 2012, 14:00–14:15, V38.01
Optical field enhancement at sharp tips — •Sebastian Thomas, Markus Schenk, Michael Krüger, Michael Förster, Lothar Maisenbacher, and Peter Hommelhoff — Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching bei München, Germany
The electric field of an electromagnetic wave is significantly enhanced at structures smaller than the wavelength. We investigate field enhancement of laser pulses at sharp nanotips by performing numerical simulations with the finite-difference time-domain (FDTD) method. In the simulations, we observe a highly localized enhanced field at the apex of the tips. By analyzing a large series of simulations, we characterize the magnitude of the enhancement for a wide range of parameters and find that it mainly depends on the tip's radius of curvature and the optical properties of the tip material. We will present our results, which clarify the mechanism behind the enhancement, and compare the simulation data with experimental data.
Experimentally, we study the photoemission of electrons from a nanometric metal tip under laser illumination . The enhanced electric field enables us to observe strong-field effects even at low pulse energies. The magnitude of the field enhancement found in the simulations broadly agrees with our experimental data.
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