Localized excitation of magnetic fields using ultrashort optical pulses*

The interaction of optical pulses with magnetic materials has lately attracted a great deal of attention due to its potential applications, notably, the all- optical helicity dependent magnetic recording [1]. The experimental evidence readily shows that this interaction gives rise to a magnetic torque [2] whose nature has been the subject of much debate and discussion[3].

In this work we examine the interaction of fs pulses with a heavy metal in a measurement that is based the Hall effect. Short circularly polarized optical pulses are focused on a thin film of Pt that is patterned for a Hall measurement. An optically induced Hall signal is observed even in the absence of an external magnetic field indicating the generation of a localized magnetic field.

Our work opens a new avenue to explore the inner workings of this elusive interaction.  

 

[1]          C. D. Stanciu, F. Hansteen, A. V. Kimel, A. Kirilyuk, A. Tsukamoto, A. Itoh, and T. Rasing, "All-Optical Magnetic Recording with Circularly Polarized Light", Physical Review Letters 99, 047601 (2007).

[2]          A. Capua, C. Rettner, S.-H. Yang, T. Phung, and S. S. P. Parkin, "Ensemble-averaged Rabi oscillations in a ferromagnetic CoFeB film", Nature Commun. 8, 16004 (2017).

[3]          A. Kirilyuk, A. V. Kimel, and T. Rasing, "Ultrafast optical manipulation of magnetic order", Reviews of Modern Physics 82, 2731 (2010).