10 years ago the German physicist Ortvin Hess in the article "Storage of Light in a Trap for a Rainbow from Metamaterials" has made the assumption that light can be slowed down by means of new materials.
It is known that velocity of light in a vacuum is about 300 thousand km/s, however when passing through transparent materials (water, glass) it slightly "brakes". By calculations of scientists if to reduce this speed in millions of times, then light could be used, for example, for transfer and storage of information.