Silicon coating puts brakes on red light

Bursts of laser light lasting less than a trillionth of a second have allowed scientists to observe chemical reactions in real-time, image biological samples, build nanostructures, and send long-distance, high-bitrate optical communications.

Ultrashort laser pulses applied in the visible spectrum must overcome a fundamental difficulty, namely that red light travels faster than blue light through transparent materials like glass. When an ultrashort laser pulse passes through a glass lens, the tightly packed wavelengths of light separate and compromise the usefulness of the beam.

Solutions to this problem involve additional components that increase the size and bulk of optical devices.

MORE FROM MATERIALS

Now, researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), in collaboration with Graz University of Technology in Austria, have developed a silicon coating that, when applied to the surface of a glass lens, can counteract the effects of dispersion.