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arXiv · 1407.4010

Sub-diffraction sub-100 ps all-optical magnetic switching by passive wavefront shaping

L. Le Guyader·M. Savoini·S. El Moussaoui·M. Buzzi·A. Tsukamoto·A. Itoh·A. Kirilyuk·Th. Rasing·A. V. Kimel·F. Nolting
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Abstract

The recently discovered magnetization reversal driven solely by a femtosecond laser pulse has been shown to be a promising way to record information at record breaking speeds. Seeking to improve the recording density has raised intriguing fundamental question about the feasibility to combine the ultrafast temporal with sub-wavelength spatial resolution of magnetic recording. Here we report about the first experimental demonstration of sub-diffraction and sub-100 ps all-optical magnetic switching. Using computational methods we reveal the feasibility of sub-diffraction magnetic switching even for an unfocused incoming laser pulse. This effect is achieved via structuring the sample such that the laser pulse experiences a passive wavefront shaping as it couples and propagates inside the magnetic structure. Time-resolved studies with the help of photo-emission electron microscopy clearly reveal that the sub-wavelength switching with the help of the passive wave-front shaping can be pushed into sub-100 ps regime.

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L. Le Guyader, M. Savoini, S. El Moussaoui, M. Buzzi, A. Tsukamoto, A. Itoh, A. Kirilyuk, Th. Rasing, A. V. Kimel, F. Nolting. 2014-07-15. Sub-diffraction sub-100 ps all-optical magnetic switching by passive wavefront shaping. https://doi.org/10.1038/ncomms6839

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