“We wanted to make an analog of that kind of laser but for SAWs.”On top of a wafer of silicon, the team applied a thin layer of lithium niobate. A well-known material in optoelectronics and telecommunications circles, lithium niobate is piezoelectric, meaning it produces an oscillating electric field when it vibrates (and vice versa). Related Story How the Classic Internet Dial-Up Sound WorksApply an electric field to this material, and waves form in the lithium niobate, creating a “sloshing” back-and-forth of SAWs. The researchers report that they created SAW ripples at a rate of 1 gigahertz, but believe that they can up that speed to hundreds of gigahertz (typical SAW devices top out at around 4 gigahertz). “This phonon laser was the last domino standing that we needed to knock down,” Eichenfield said in a press statement.