In the past few years, there have been some encouraging developments on the road toward integrated circuits that operate on photons rather than electrons—so-called photonic ICs. Most notable among these have been developments in plasmonics, which have made it possible to shrink the wavelengths of light to fit into the tight dimensions of today’s ICs.
While graphene and silicon together have been partly responsible for enabling these advancements in plasmonics, silicon has not been so friendly to the lasers that would provide the light source for these photonic ICs. One of silicon’s intrinsic electronic properties, its indirect band gap, makes its ability to generate light from an electrical current pretty feeble.
Now, researchers at Yale University may have found a solution to silicon’s poor laser performance. They’ve turned to an unusual type of laser that uses not just light but sound to create the optical amplification: a Brillouin laser.