Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 17: INNOMAG e.V. Diplom-/Master Prize 2019

MA 17.2: Vortrag

Dienstag, 2. April 2019, 11:50–12:10, H48

Design of cavity optomagnonic systems with magnetic textures: Coupling a magnetic vortex to light — •Jasmin Graf — Max Planck Institute for the Science of Light, Staudtstraße 2, 91058 Erlangen, Germany

In optomagnonics, light coherently couples to collective magnetic excitations in solid state systems. This topic is currently of high interest for quantum information processing at the nanoscale. A unique feature of optomagnonic systems is the possibility of coupling light to magnetic excitations on top of a textured magnetic ground state. A paradigmatic example of a magnetic texture is a vortex, which is the ground state configuration of a magnetic microdisk. The lowest energy magnetic excitations of this system are localized at the vortex core. In our work, we derive the optomagnonic coupling for magnetic textures and develop a numerical method to evaluate the coupling. We apply our results to the case of the micromagnetic disk. We show that the localized magnon modes can coherently couple to light confined in whispering gallery modes of the disk. The resulting optomagnonic coupling has a rich structure, and can be tuned by an externally applied static magnetic field. Our results predict cooperativities at maximum photon density (an important figure of merit in these systems) of the order of C ≈ 0.01 by proper engineering of these structures. These values show promise for future design of cavity optomagnonic systems.

Reference: J. Graf, H. Pfeifer, F. Marquardt, S. Viola-Kusminskiy; PRB 98, 241406(R) (2018)