Polariton excitation in epsilon-near-zero slabs: Transient trapping of slow light

Abstract

We numerically investigate the propagation of a spatially localized and quasi-monochromatic electromagnetic pulse through a slab with Lorentz dielectric response in the epsilon-near-zero regime, where the real part of the permittivity vanishes at the pulse carrier frequency. We show that the pulse is able to excite a set of virtual polariton modes supported by the slab, the excitation undergoing a generally slow damping due to absorption and radiation leakage. Our numerical and analytical approaches indicate that in its transient dynamics the electromagnetic field displays the very same enhancement of the field component perpendicular to the slab, as in the monochromatic regime. The transient trapping is inherently accompanied by a significantly reduced group velocity ensuing from the small dielectric permittivity, thus providing a novel platform for achieving control and manipulation of slow light.

Self-organization of frozen light in near-zero-index media with cubic nonlinearity

“…1 in the lossless limit , together with the phase and group velocities . Note the cutoff of TEM waves at the plasma frequency , where the medium enters the ENZ regime, the phase velocity diverges, and the group velocity vanishes 22 23 24 .…”

“…Physical systems enabling either slow or fast light 16 17 18 naturally enhance radiation-matter interaction, thus boosting nonlinear processes that can be efficiently used for active light control 19 , all-optical switching, and modulation 20 21 . In particular, near-zero-index (NZI) media can slow down light propagation 22 23 24 and enable extreme nonlinear dynamics 25 , enhanced second and third harmonic generation 26 , active control of tunneling 27 , optical switching, and bistable response 28 . These materials naturally exist in nature, for example plasmas, transparent conductors, and metals near their bulk plasma frequency 29 .…”

Self-interaction of ultrashort pulses in an epsilon-near-zero nonlinear material at the telecom wavelength

“…In the recent decade, the epsilon-near-zero (ENZ) materials have drawn much interest in studies of plasmonic metamaterials [1] and photonics [2,3]. By tuning its permittivity to a near-zero value, the ENZ material can feature a refractive index much lower than 1 and other extraordinary optical properties, such as electromagnetic energy tunneling [4], directive emission with invariable phase [5], amplification of electric field [6], enhancement of nonlinearity [7], pulse shaping and tailoring [8,9], slow-light trapping [10], and the creation of confined ENZ modes [11,12].…”

Enhanced nonlinear effects in pulse propagation through epsilon‐near‐zero media

“…Such a key feature has been exploited to conceive setups where ultra‐narrow ENZ channels are able to ”squeeze” electromagnetic waves at will , and to develop new paradigms of devices for tailoring the antenna radiation pattern . In addition, ENZ metamaterials have also been shown to support a rich phenomenology of surface waves , to achieve perfect absorption , to enhance spatial dispersion effects , and to support novel cloaking mechanisms .…”

“…Such a key feature has been exploited to conceive setups where ultra-narrow ENZ channels are able to "squeeze" electromagnetic waves at will [16][17][18][19], and to develop new paradigms of devices for tailoring the antenna radiation pattern [20][21][22]. In addition, ENZ metamaterials have also been shown to support a rich phenomenology of surface waves [23][24][25][26][27][28][29], to achieve perfect absorption [30], to en-and for the enhancement of second-harmonic generation efficiency [48]. Recently the existence of frozen light in ENZ media with cubic nonlinearity has been theoretically predicted [49].…”