All-optical control in metamaterial-dielectric waveguides

We explore the possibility of all-optical control of weak signals in waveguides having a dielectric core and a metamaterial cladding (metamaterial-dielectric waveguide). To this end we present a characterization of slab and cylindrical metamaterial-dielectric waveguides. To describe the permittivity of the metamaterial we use the lossy Drude model and for the permeability we use a lossy Lorentz-Drude model. We find that metamaterial-dielectric waveguides support modes with lower attenuation than metal-dielectric guides through expulsion of the fields from the metamaterial. The field expulsion also provides good transverse confinement in the cylindrical guide. We propose using slow light to effect all-optical control in metamaterial waveguides. To slow the light, we employ electromagnetically induced transparency by pumping, with a strong control field, 3-level atoms embedded in the dielectric core. Pumping the atoms using a waveguide mode elicits a nonlinear response that results in a spatially graded refractive index in the core of the guide. The resulting refractive index depends on the strength and the transverse profile of the control field. We use the results of the aforementioned characterization to determine the properties of the control field (e.g. transverse profile). A signal field can then be manipulated by changing the parameters of the control field. All-optical control schemes, such as this, could be exploited for ultra-fast optical switches or quantum information processing applications.