We review recent theoretical and experimental in progress in the realisation of slow and stopped light by the 'trapped rainbow' principle in optical metamaterials featuring negative electromagnetic parameters (permittivity/permeability and/or refractive index). We explain how and why these structures can enable complete stopping of light even in the presence of disorder and, simultaneously, dissipative losses. Using full-wave numerical simulations we show that the incorporation of thin layers made of an active medium adjacently to the core layer of a negative-refractive-index waveguide can completely remove dissipative losses - in a slow-light regime where the effective index of the guided wave is negative. © 2010 SPIE.

Metamaterials exhibiting negative electromagnetic parameters can enable a multitude of exciting applications, but currently their performance is limited by the occurrence of losses-particularly radiation losses, which dominate over their dissipative counterparts even in the optical regime. Here, a metamaterial configuration is conceived that judiciously generalizes the traditional electromagnetically induced transparency (EIT) scheme-by which radiation losses can be restrained-in such a way that EIT can be observed and exploited in negative-magnetic metamaterials. Analytic theory and three-dimensional simulations unveil the required route: introduction of poor-conductor meta-atoms next to the good-conductor meta-atoms of a magnetic metamaterial. This setup results in a frequency band where the metamaterial remains negative-magnetic, while its loss-performance dramatically improves owing to suppression of radiation damping. Furthermore, we show that placing the two meta-atoms on orthogonal planes gives rise to a passive anisotropic metamaterial exhibiting permeabilities with negative real parts (Re {μ} <0) and active imaginary parts (Im {μ} >0 for an e+iωt time dependence) along its principal crystallographic axes. © 2010 The American Physical Society.

We review recent theoretical and experimental breakthroughs in the realm of slow and stopped light in structured photonic media featuring negative electromagnetic parameters (permittivity/permeability and/or refractive index). We explain how and why these structures can enable complete stopping of light even in the presence of disorder and, simultaneously, dissipative losses. Using full-wave numerical simulations we show that the incorporation of thin layers made of an active medium adjacently to the core layer of a negative-refractive- index waveguide can completely remove dissipative losses - in a slow-light regime where the effective index of the guided wave is negative. We, also, review and compare several 'trapped rainbow' schemes that have recently been proposed for slowing and stopping light. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Using full-wave simulations we show how the incorporation of thin layers made of an active medium adjacently to the core layer of a negative-index slow-light waveguide can completely remove dissipative optical losses. © 2010 Optical Society of America.

We investigate on the basis of a full three-dimensional spatio-temporal Maxwell-Bloch approach the possibility of complete loss compensation in non-bianisotropic negative refractive index (NRI) metamaterials. We show that a judicious incorporation of optically pumped gain materials, such as laser dyes, into a double-fishnet metamaterial can enable gain in the regime where the real part n′ of the resulting effective refractive index (n = n′ + in″) is negative. It is demonstrated that a frequency band exists for realistic opto-geometric and material (gain/loss) parameters where n′ < 0 and simultaneously n″ < 0 hold, resulting in a figure-of-merit that diverges at two distinct frequency points. Having ensured on the microscopic, meta-molecular level that realistic levels of losses and even gain are accessible in the considered optical frequency regime we explore the possibility of compensating propagation losses in a negative refractive index slow-light metamaterial heterostructure. The heterostructure is composed of a negative refractive index core-layer bounded symmetrically by two thin active cladding layers providing evanescent gain to the propagating slow light pulses. It is shown that backward-propagating light - having anti-parallel phase and group velocities and experiencing a negative effective refractive index - can be amplified inside this slow-light waveguide structure. Our results provide a direct and unambiguous proof that full compensation of losses and attainment of gain are possible on the microscopic as well as the macroscopic level in the regime where the non-bianisotropic refractive index is negative - including, in particular, the regime where the guided light propagates slowly. © 2010 SPIE.

On the basis of a full-vectorial three-dimensional Maxwell-Bloch approach we investigate the possibility of using gain to overcome losses in a negative refractive index fishnet metamaterial. We show that appropriate placing of optically pumped laser dyes (gain) into the metamaterial structure results in a frequency band where the nonbianisotropic metamaterial becomes amplifying. In that region both the real and the imaginary part of the effective refractive index become simultaneously negative and the figure of merit diverges at two distinct frequency points. © 2010 The American Physical Society.