Photonic chip separates mixed light beams
Researchers at Stanford University and ISTA have developed a fingernail-sized photonic chip capable of separating partially coherent light into independent beams.
Researchers from Stanford University and the Institute of Science and Technology Austria (ISTA) have demonstrated a photonic integrated circuit (PIC) that can automatically separate mixed light into distinct, mutually incoherent beams.
Published in Nature Photonics, the research represents the first experimental demonstration of on-chip separation of partially coherent light into its mutually incoherent components, a concept explored theoretically since the 1980s.
The chip uses integrated optical architectures and algorithms to identify the underlying coherence modes of incoming light and direct them into separate outputs.
In experiments involving two and three infrared lasers, the device successfully separated mixed light into independent beams.
"Our chip learns the underlying coherence modes of an unknown light field and physically directs them into separate outputs," said Shanhui Fan, professor of electrical engineering at Stanford University. "That gives us a way to analyze the light's spatial coherence while keeping the separated light available for further processing."
The technology could enable new approaches to optical imaging, microscopy, astronomy and sensing by extracting information that conventional imaging systems may struggle to distinguish.
Researchers are also collaborating with NASA to investigate whether the approach could help distinguish overlapping light sources from distant stars and exoplanets.
The findings highlight the potential of integrated photonics to perform increasingly sophisticated optical processing functions on compact chips, extending their applications beyond conventional optical communications.
