Slow and Stopped Light in Metamaterials

Abstract

Since ancient times, people have experimented with light. Today we are far more advanced in how we work with his ubiquitous energy. Starting with 19th-century experimentation, we began to explore controlling how light interacts with matter. Combining multiple materials in complex structures let us use light in new ways. It is worthwhile mentioning that the extremely large speed of light is a tremendous asset but one may face with challenges aiming to control, store, or shrink beyond its wavelength. Reducing the speed of light down to zero is of fundamental scientific interest. The manipulation of light group velocity in a terahertz metamaterial without needing a dark resonator, but utilizing instead two concentric split-ring bright resonators (meta-atoms) exhibiting a bright Fano-resonance in close vicinity of a bright Lorentzian resonance to create a narrowband transmittance is reported. The former phenomenon could open the wide avenues for the important photonic applications, some of which are as yet fundamentally inaccessible. These include cavity-free, low-threshold nanolasers, novel solar cell designs for efficient harvesting of light, nanoscale quantum information processing (owing to the enhanced density of states), as well as enhanced biomolecular sensing. For instance, plasmon rulers can be used to determine nanoscale distances within chemical or biological species. Devices that can buffer or delay the light pulse are key components for both optical communication networks and quantum information processing systems. Large pulse delay (or “slow light”) is achievable with many methods/structures including electromagnetically induced transparency (EIT), quantum-dot semiconductor optical amplifiers, photonic crystal waveguide, direct-coupled resonators, coherent population oscillations, stimulated Brillouin scattering, stimulated Raman scattering, and surface plasmon polaritons.