Although still three to five years away, computers based on light signals instead of electrical signals might put the Pentium chip to shame. Since 1992, scientists knew that the holes in porous silicon contain microscopic structures that emit light when electric current is applied. But the untreated material was fragile. Oxygen and water molecules in the air interact with the surface and create a glass-like coating that disrupts its photoluminescence properties. Jillian Buriak, assistant professor in Purdue's Department of Chemistry, discovered a way to stabilize the substrate's surface by coating the porous surface of the silicon with Lewis acid, a solution which produces a greasy coating. "Because most current technology is based on silicon, it may be relatively easy to develop the optical applications and combine them with current technologies, as the manufacturing processes are already in place," Buriak says. Porous silicon could easily serve as a flat, display area for computer screens, as well as a basis for computers that operate on light signals.