Speed of light is manipulated by material effectively than previous method

The University of Alabama researchers invented a material that manipulates the speed of light in a new, more effective way than previous methods.

Besides Kim, the paper "Impact of Substrate and Bright Resonances on Group Velocity in Metamaterial without Dark Resonator" is authored by graduate students Mohammad Parvinnezhad Hokmabadi, Ju-Hyung Kim and Elmer Rivera along with Dr. Patrick Kung, an associate professor in electrical and computer engineering.

Development of optical buffers and delay lines as essential elements of future ultrafast all optical communication networks which is lead by slow light and could meet the ever-increasing demands for long-distance communications.

Kim's research investigates the interaction between light, a form of electromagnetic waves called photons, and matter to attain combined spectroscopic sensing and near field imaging capabilities by utilizing terahertz waves. Terahertz waves exist in the electromagnetic spectrum between infrared light and microwaves, and are promising for various applications such as security, chemical and biological sensing, biomedical imaging, and non-destructive manufacturing inspection.

For the experiment, the research group used terahertz waves, but the scientific findings can be applied to other wavelengths, including visible light, Kim said.

In unencumbered air, light is generally accepted to travel at a constant speed, but it can be slowed by passing through a material. Water, for instance, bends, or refracts, light. While the human eye can detect changes in the speed of light through bended images such as through eye glasses or curved mirrors, the speed of light is not substantially slower with simple refraction.

An emerging class of materials called metamaterials can be engineered with properties not found naturally, which can be structured to interact with light to slow or stop it. Unlike the best known methods for slowing light that involved cold atoms, metamaterials use no energy and are much less complex to implement. They show promise in various applications such as filters, modulators, invisible cloaking devices, superlenses and perfect absorber.