Abstract

Floquet states have been the subject of great research interest since Zel’dovich’s pioneering work on the quasienergy of a quantum system influenced by a temporally periodic action. Nowadays, periodic modulation of the system Hamiltonian is achieved mostly by microwaves, leading to novel exciting phenomena in condensed matter physics. On the other hand, nonthermal optical control of magnetization at picosecond time scales is currently a highly appealing research topic for potential applications in magnetic data storage. Here we combine these two concepts to theoretically investigate Floquet states in the system of exchange-coupled spins in a ferromagnet. Periodic perturbation of the magnetization of an iron–garnet film by circularly polarized femtosecond laser pulses is shown to establish the magnetization dynamics behaving like Floquet states. An external magnetic field allows tuning of the Floquet states, leading to pronounced increase in the precession amplitude by one order of magnitude at the center of the Brillouin zone, i.e., when the precession frequency is a multiple of the laser pulse repetition rate. Floquet states might potentially allow for parametric generation of magnetic oscillations. The observed phenomena expand the capabilities of coherent ultrafast optical control of magnetization and pave the way for their application in quantum computation or data processing.

© 2019 Optical Society of America

Optical excitation of spin waves in epitaxial iron garnet films: MSSW vs BVMSW

A. I. Chernov, M. A. Kozhaev, I. V. Savochkin, D. V. Dodonov, P. M. Vetoshko, A. K. Zvezdin, and V. I. Belotelov
Opt. Lett. 42(2) 279-282 (2017)

Enhanced fully optically pumped magnetic resonance with optical sideband auxiliary pumping

Z. Y. Jiang, X. C. Liu, P. W. Lin, J. F. Qu, and H. P. Liu
Opt. Lett. 45(1) 105-108 (2020)

Control of the phase of the magnetization precession excited by circularly polarized femtosecond-laser pulses

Alexander I. Chernov, Mikhail A. Kozhaev, Anastasiia Khramova, Alexander N. Shaposhnikov, Anatoly R. Prokopov, Vladimir N. Berzhansky, Anatoly K. Zvezdin, and Vladimir I. Belotelov
Photon. Res. 6(11) 1079-1083 (2018)

Topological Floquet bound states in the continuum

Chunyan Li, Yaroslav V. Kartashov, and Vladimir V. Konotop
Opt. Lett. 47(19) 5160-5163 (2022)

Ultrafast light-driven magneto-optical nonlinearity in ferromagnetic heterostructures

Yexin Jiang, Zhangshun Li, Zhuoyi Li, Zuanming Jin, Xianyang Lu, Yongbing Xu, Yan Peng, and Yiming Zhu
Opt. Lett. 48(8) 2054-2057 (2023)