SPICE Workshop on Spin textures: Magnetism meets Plasmonics, July 23rd - 25th 2024
Martin Aeschlimann
Department of Physics and Research Center OPTIMAS, RPTU Kaiserslautern-Landau, 67663 Kaiserslautern, Germany
The transformation of light carrying spin angular momentum (SAM) into an optical field vortex carrying angular momentum (OAM) has been of wide interest in recent years [1]. In our work, we investigate the superposition of two fields, each carrying one of these degrees of freedom, and focus on the transfer of the resulting angular momentum to matter. For this purpose, we measured the interaction between 3D light carrying axial SAM and 2D plasmon-polariton vortices carrying high-order transverse OAM [1].
The interaction is mediated by two-photon absorption at a gold surface, and the resulting angular momentum mixing is imprinted into matter by excitation of electrons, which are photo-emitted into the vacuum and detected by photoemission electron microscopy (PEEM). We show experimentally and theoretically that the absorptive nature of this interaction leads to both single and double photon-plasmon angular momentum mixing processes corresponding to different quantum paths of electron excitation [2,3].
[1] Spektor et al., Science 355, 1187-1191 (2017)
[1] Spektor et al., PRX 9, 021031 (2019)
[3] Prinz et al., ACS Photonics, 10, 340−367 (2023)