Silica Conductor...

Optics and Photonics

Usually, if you blast enough light into an insulator, it will blow up quickly or break down slowly. But today, a pair of papers published in Nature describe using very intense femtosecond laser pulses that not only do not damage the material, but also induce electrical currents in an otherwise insulating dielectric—specifically a fused silica prism (Nature, DOI: 10.1038/nature11567; Nature, Advanced DOI: 10.1038/nature11720).

The work is exciting because insulators that can quickly change into conductors (and back into insulators again) could be used for signal switching. Today's fastest semiconductor switching is measured in terahertz, but light-induced switching in insulators, such as demonstrated in these papers, could work at petahertz rates—more than 10,000 times the rate of current electronics. In the near-term, it could also make possible petahertz (10¹⁵ hertz) metrology.

Optics an Photonics: Ultrafast Light Turns Insulator into a Conductor, Yvonne Carts-Powell