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arXiv · 1601.07088

Optically induced metal-to-dielectric transition in Epsilon-Near-Zero metamaterials

R. M. Kaipurath·M. Pietrzyk·L. Caspani·T. Roger·M. Clerici·C. Rizza·A. Ciattoni·A. Di Falco·D. Faccio
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Abstract

Epsilon-Near-Zero materials exhibit a transition in the real part of the dielectric permittivity from positive to negative value as a function of wavelength. Here we study metal-dielectric layered metamaterials in the homogenised regime (each layer has strongly subwavelength thickness) with zero real part of the permittivity in the near-infrared region. By optically pumping the metamaterial we experimentally show that close to the Epsilon-Equal-to-Zero (EEZ) wavelength the permittivity exhibits a marked transition from metallic (negative permittivity) to dielectric (positive permittivity) as a function of the optical power. Remarkably, this transition is linear as a function of pump power and occurs on time scales of the order of the 100 fs pump pulse that need not be tuned to a specific wavelength. The linearity of the permittivity increase allows us to express the response of the metamaterial in terms of a standard third order optical nonlinearity: this shows a clear inversion of the roles of the real and imaginary parts in crossing the EEZ wavelength, further supporting an optically induced change in the physical behaviour of the metamaterial.

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R. M. Kaipurath, M. Pietrzyk, L. Caspani, T. Roger, M. Clerici, C. Rizza, A. Ciattoni, A. Di Falco, D. Faccio. 2016-01-26. Optically induced metal-to-dielectric transition in Epsilon-Near-Zero metamaterials. https://doi.org/10.1038/srep27700

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