Master thesis

Ultrafast electron and phonon dynamics of nanoobjects

Illumining a metallic nanotip with laser pulses, optical electric fields are enhanced at the tip apex. These enhanced fields permit coherent electron emission from the tip apex. Varying the laser polarization can substantially change the spatial distribution of the local electric fields on the tip apex [1]. In effect, an ultrafast pulsed coherent electron source with emission site selectivity of a few ten nanometers can be realized [2]. Using such an electron source, we are developing a new method to observe ultrafast electron and phonon dynamics of nanoobjects, including molecule-nanotip heterostructures. The animation shows an example of the photoemission from nanotips in laser fields with rotating polarization. The electrons are recorded by a two-dimensional detector, which allows to measure the emission patterns from the tip [1, 2]. An electron analyzer can be used to measure energy spectra of electrons emitted from the tip apex [3, 4]. We are currently investigating the interference of the matter waves emitted from such nanotips in intense few-cycle laser pulses.

If you are interested in this project, please contact:
Dr. Hirofumi Yanagisawa (office: w132, Am Coulombwall 1, 85748 Garching)
Office Phone: 08928914110

[1] Hirofumi Yanagisawa et al., Phys. Rev. Lett. 103, 257603 (2009)
[2] Hirofumi Yanagisawa et al., Sci. Rep. 7:12661 (2017)
[3] Hirofumi Yanagisawa et al., Phys. Rev. Lett. 107, 087601 (2011)
[4] Hirofumi Yanagisawa et al., Sci. Rep. 6:35877 (2016)

24th November 2017