Experimental demonstration of near-infrared epsilon-near-zero multilayer metamaterial slabs

Abstract

Near-infrared epsilon-near-zero (ENZ) metamaterial slabs based on silver-germanium (AgGe) multilayers are experimentally demonstrated. Transmission, reflection and absorption spectra are characterized and used to determine the complex refractive indices and the effective permittivities of the ENZ metamaterial slabs, which match the results obtained from both the numerical simulations and the optical nonlocalities analysis. A rapid post-annealing process is used to reduce the collision frequency of silver and therefore decrease the optical absorption loss of multilayer metamaterial slabs. Furthermore, multilayer grating structures are studied to enhance the optical transmission and also tune the location of ENZ wavelength. The demonstrated near-infrared ENZ multilayer metamaterial slabs are important for realizing many exotic applications, such as phase front shaping and engineering of photonic density of states.

Unbounded spatial spectrum of propagating waves in a polaritonic wire medium

“…Of course, optical losses decrease this effect, however, in work 17 it was experimentally shown (in this case for a stack of silver-germanium bilayers) that even the radiative Purcell factor -the gain in power radiated to free space one achieves one order of magnitude for emitters located on the surface. Further, in Ref.…”

Unbounded spatial spectrum of propagating waves in a polaritonic wire medium

“…I, a topological transition happens not because the effective permittivity changes its sign over the frequency axis as in Refs. [16,20]. In our case, the effective permittivity changes the sign over the wave-vector axis, and both closed-surface and open-surface branches exist in the reciprocal space together and touch one another.…”

“…The phenomenon arises from the nonlocal response of the wire medium and this kind of topological phase transition is different from that studied in Refs. [16,20,21]. It provides an unbounded spatial spectrum which should cause a high Purcell factor due to the absence of any cutoff for spatial harmonics.…”

Propagation properties of Gaussian beam through a asymmetric negative index slab system by transfer matrix

“…Negative refraction index slab system is a new optical system [1], a lot of scholars researched on this system [9][10][11][12][13], but their models are symmetrical, that is, in the negative index slab sides, either free space or the same positive refractive index material. In our system, both the negative index slab sides are two different positive refractive index materials, which we call asymmetric negative index slab system.…”