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1,000-fold enhancement of light-induced magnetism in plasmonic Au nanoparticles (Conference Presentation)

Paper Abstract

Strategies for ultrafast optical control of magnetism have been a topic of intense research for several decades because of the potential impact in technologies such as magnetic memory spintronics and quantum computation, as well as the opportunities for non-linear optical control and modulation in applications such as optical isolation and non-reciprocity. Here we report the first experimental quantification of optically induced magnetization in plasmonic Au nanoparticles due to the inverse Faraday effect (IFE). The induced magnetic moment in nanoparticles is found to be ~1,000x larger than that observed in bulk Au, and ~20x larger than the magnetic moment from optimized magnetic nanoparticle colloids such as magnetite. Furthermore, the magnetization and demagnetization kinetics are instantaneous within the sub-picosecond time resolution of our study. By controlling the relative polarization difference between the pump and probe beams in an ultrafast time-resolved study, the contribution of the IFE and the optical Kerr effect (OKE) was clearly distinguished. Our experiments measured optical rotation indicative of magnetization that is parallel or anti-parallel with a pump beam depending on the helicity of the excitation. Additionally, we observe optically induced magnetization that is ~1,000 times larger than in bulk Au, and linearly proportional with incident optical power. We anticipate these results may be of great interest in the photonics community for application in ultrafast optical control of magnetic properties, and for all-optical methods of optical isolation that do not require externally applied magnetic fields.

Paper Details

Date Published: 9 September 2019
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Proc. SPIE 11080, Metamaterials, Metadevices, and Metasystems 2019, 110801G (9 September 2019); doi: 10.1117/12.2529704
Show Author Affiliations
Matthew T. Sheldon, Texas A&M Univ. (United States)
Oscar Hsu-Cheng Cheng, Texas A&M Univ. (United States)


Published in SPIE Proceedings Vol. 11080:
Metamaterials, Metadevices, and Metasystems 2019
Nader Engheta; Mikhail A. Noginov; Nikolay I. Zheludev, Editor(s)

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