A new wavefront-sensing technology called PEEPSS uses photonic lanterns to suppress starlight, letting ground-based telescopes see Earth-like exoplanets that were previously invisible.
Finding a habitable planet around another star is one of astronomy's hardest problems. The planet is billions of times fainter than its parent star, and atmospheric turbulence blurs the image. A new sensor called PEEPSS — the Photonic-Enabled ExoPlanet Spectroscopic Sensor — tackles both problems at once using a device borrowed from fiber optics: the photonic lantern.
A photonic lantern is a tapered optical fiber that splits a single beam of light into multiple separate channels. When placed at the focal plane of a telescope, it acts as a wavefront sensor — measuring exactly how the atmosphere has distorted the incoming starlight. By feeding this information back to a deformable mirror, the system can cancel out atmospheric blur in real time. What makes PEEPSS special is that it combines science and wavefront sensing into a single optical path, eliminating a persistent problem called non-common-path error that has limited previous coronagraph designs.
NASA's planned Habitable Worlds Observatory (HWO) is a flagship mission designed to directly image Earth-like planets around nearby stars. But the mission is still years away, and ground-based telescopes like the Extremely Large Telescope (ELT) could get there first if they can overcome the atmospheric challenge. PEEPSS, developed by a team at the University of Sydney and collaborators, is designed to bridge this gap. The three-year project is building and testing prototype photonic lantern systems in both laboratory and real telescope environments.
The technology has applications beyond planet hunting. Photonic-lantern wavefront sensing can improve any high-contrast imaging task — from spotting faint companion stars to resolving the surfaces of distant stars. It could also be used in free-space optical communications, where maintaining a clean signal through atmospheric turbulence is equally critical.