Jasmin Graf

Bio: Jasmin Graf is an academic researcher from Max Planck Society. The author has contributed to research in topics: Magnon & Coupling (physics). The author has an hindex of 3, co-authored 4 publications receiving 98 citations.

Cavity optomagnonics with magnetic textures: Coupling a magnetic vortex to light

Abstract: A unique feature of cavity optomagnonics is the possibility of coherently coupling light to spin excitations on top of magnetic textures. Here, the authors propose a cavity-optomagnonic system with a nonhomogeneous magnetic ground state, namely, a vortex in a magnetic microdisc. Using both analytical and computational methods, they study the cavity-enhanced coupling between optical whispering gallery modes and magnon modes, localized at the vortex. The results, both in terms of value and tunability of the coupling, point to the promise of engineered optomagnonic systems for quantum information platforms.

Design of an optomagnonic crystal: Towards optimal magnon-photon mode matching at the microscale

Abstract: The authors propose an optomagnonic crystal consisting of a Faraday-active magnetic dielectric which is periodically patterned at the microscale and supports both photon and magnon modes.

Design of an optomagnonic crystal: towards optimal magnon-photon mode matching at the microscale

Abstract: We put forward the concept of an optomagnonic crystal: a periodically patterned structure at the microscale based on a magnetic dielectric, which can co-localize magnon and photon modes. The co-localization in small volumes can result in large values of the photon-magnon coupling at the single quanta level, which opens perspectives for quantum information processing and quantum conversion schemes with these systems. We study theoretically a simple geometry consisting of a one-dimensional array of holes with an abrupt defect, considering the ferrimagnet Yttrium Iron Garnet (YIG) as the basis material. We show that both magnon and photon modes can be localized at the defect, and use symmetry arguments to select an optimal pair of modes in order to maximize the coupling. We show that an optomagnonic coupling in the kHz range is achievable in this geometry, and discuss possible optimization routes in order to improve both coupling strengths and optical losses.

A Finite-Difference Time-Domain approach for dispersive magnetic media

Abstract: We extend the Finite-Difference Time-Domain method to treat dispersive magnetic media by incorporating magneto-optical effects through a frequency-dependent permittivity tensor. For benchmarking our method, we consider the light scattering on a magnetic sphere in the Mie regime. We first derive the analytical scattering expressions which predict a peak broadening in the scattering efficiency due to the atomic energy level splitting in the presence of a magnetic field, together with an additional rotated part in the scattered field profile due to the Faraday rotation. We show that our numerical method is able to capture the main scattering features and discuss its limitations and possible improvements in accuracy.

Electrodynamics Of Continuous Media

Abstract: Thank you for reading electrodynamics of continuous media. Maybe you have knowledge that, people have look numerous times for their chosen books like this electrodynamics of continuous media, but end up in infectious downloads. Rather than reading a good book with a cup of tea in the afternoon, instead they cope with some malicious bugs inside their computer. electrodynamics of continuous media is available in our book collection an online access to it is set as public so you can get it instantly. Our book servers saves in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Kindly say, the electrodynamics of continuous media is universally compatible with any devices to read.

Hybrid quantum systems based on magnonics

Abstract: Engineered quantum systems enabling novel capabilities for communication, computation, and sensing have blossomed in the last decade. Architectures benefiting from combining distinct and complementary physical quantum systems have emerged as promising platforms for developing quantum technologies. A new class of hybrid quantum systems based on collective spin excitations in ferromagnetic materials has led to the diverse set of experimental platforms which are outlined in this review article. The coherent interaction between microwave cavity modes and collective spin-wave modes is presented as the backbone of the development of more complex hybrid quantum systems. Indeed, quanta of excitation of the spin-wave modes, called magnons, can also interact coherently with optical photons, phonons, and superconducting qubits in the fields of cavity optomagnonics, cavity magnomechanics, and quantum magnonics, respectively. Notably, quantum magnonics provides a promising platform for performing quantum optics experiments in magnetically-ordered solid-state systems. Applications of hybrid quantum systems based on magnonics for quantum information processing and quantum sensing are also outlined briefly.

Generation of coherent spin-wave modes in yttrium iron garnet microdiscs by spin-orbit torque

Abstract: In recent years, spin–orbit effects have been widely used to produce and detect spin currents in spintronic devices. The peculiar symmetry of the spin Hall effect allows creation of a spin accumulation at the interface between a metal with strong spin–orbit interaction and a magnetic insulator, which can lead to a net pure spin current flowing from the metal into the insulator. This spin current applies a torque on the magnetization, which can eventually be driven into steady motion. Tailoring this experiment on extended films has proven to be elusive, probably due to mode competition. This requires the reduction of both the thickness and lateral size to reach full damping compensation. Here we show clear evidence of coherent spin–orbit torque-induced auto-oscillation in micron-sized yttrium iron garnet discs of thickness 20 nm. Our results emphasize the key role of quasi-degenerate spin-wave modes, which increase the threshold current.