Researchers at Wayne State University in Detroit have used a magnet and a shower of microwaves to reduce the redness of rubies and increase their transparency. Although the method, called electromagnetically induced transparency, already had proved effective on gases, the Wayne State project was the first work done on solid-state materials, said Yang Zhao, one of the researchers.
The team believes that varying the transparency of an optical medium could be helpful in bit storage in quantum computers and in making optical computer switches. Lasers with lower power could be developed by decreasing the light-generating medium's ability to absorb light.