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MetaMAT’s 38th webinar 20042021 Presentation Paloma Arroyo Huidobro
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Seminar 38, Tuesday 21 April 2021, 14:00 (London Time) • Title: Space-time metamaterials: dragging and amplifying light • Speaker: Paloma Arroyo Huidobro (Instituto de Telecomunicações, Insituto Superior Técnico-University of Lisbon) • Abstract: In this talk I will consider space-time metamaterials of travelling-wave type [1] and present a theory of homogenisation of these modulated media [2]. This framework provides analytical expressions for the effective permittivity, permeability and magnetoelectric coupling of these media in the long wavelength limit. From the derived parameters we will see how it is possible to achieve nonreciprocal effects away from the asymmetric band gaps, and even down to the quasistatic limit if both the permittivity and permeability are modulated. This way, the synthetic motion present in these systems allows a new and tunable form of Fresnel drag effect of light in moving media [3]. The theory unveils a regime where the modulation speed approaches that of waves in the background medium where homogenisation breaks down and a new mechanism for gain emerges [4], enabling a form of nonreciprocal broadband amplification that could be realised in graphene [5]. On the other hand, temporal only modulations enable novel ways to excite surface waves from the far field [6]. • [1] Galiffi, Huidobro, and Pendry, “Space-time metamaterials” in Roadmap on multimode light shaping coordinated by Piccardo and Ginis, arXiv:2104.03550 (2021) • [2] Huidobro, Silveirinha, Galiffi and Pendry, “Homogenisation theory of space-time metamaterials” arXiv:2009.10479 (2020). • [3] Huidobro, Galiffi, Guenneau, Craster, and Pendry, “Fresnel drag in space-time modulated metamaterials” Proceedings of the National Academy of Sciences 116 (50) 24943-24948 (2019). • [4] Pendry, Galiffi and Huidobro, “A new mechanism for gain in time dependent media” arXiv:2009.12077 (2020). • [5] Galiffi, Huidobro, and Pendry, “Broadband Nonreciprocal Amplification in Luminal Metamaterials”, Physical Review Letters, 123, 206101 (2019). • [6] Galiffi, Wang, Lim, Pendry, Alù, and Huidobro, “Temporal Wood Anomalies: Smoothing the Path to the Near-Field” Physical Review letters 125, 127403 (2020). • Follow us on: www.meta-mat.org
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