Dresden 2017 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 10: Spintronics II (joint session DS, HL, MA, TT, organized by HL)
TT 10.3: Talk
Monday, March 20, 2017, 15:15–15:30, POT 151
Design of polarization degenerate photonic nanocavities for cavity-enhanced optical spin-pumping — •Tobias M. Petzak1, Sebastian Hammer1,2, and Hubert J. Krenner1,2 — 1Lehrstuhl für Experimentalphysik 1, Institut für Physik, Universität Augsburg, Universitätsstr. 1 86159 Augsburg, Germany — 2Nanosystem Initiative Munich (NIM), Schellingstraße 4, 80339 München, Germany
Defect cavities in photonic crystal membranes exhibit high quality factors and enable the efficient confinement of light within small volumes. Therefore, these nanoscale optical cavities can enhance the light-matter interaction between cavity photons and optical excitations of embedded semiconductor nanosystems.
Here, we propose and demonstrate by finite-difference-time-domain (FDTD) simulations, that
a crossed-beam cavity design [1] allows to obtain polarization-degenerate photonic modes. This is achieved by varying the geometry of the two perpendicular cavities. The resulting tunable superposition of two linear polarized modes permits for the formation of a single and completely unpolarized mode. Such polarization properties are highly desirable for optically addressing spin- and valley degrees of freedom e.g. in monolayer transition metal dichalcogenides [2]. We show that our design can be implemented on thermally grown SiO2 for which our FDTD simulations predict quality factors exceeding 300 for cavities resonant with the exciton transition of WS2.
References:
K. Riviore et al., Appl. Phys. Lett. 99, 013114 (2011)
K. F. Mak et al., Nature Nanotechnology 4, 494-498 (2012)