On-sky demonstration of second-stage wavefront control with a photonic lantern

TL;DR

This paper demonstrates the use of a photonic lantern for second-stage wavefront sensing in ground-based exoplanet imaging, improving correction of aberrations beyond traditional adaptive optics.

Contribution

It introduces a novel on-sky implementation of a photonic lantern for second-stage wavefront control, enhancing adaptive optics performance.

Findings

Successful closed-loop wavefront error correction using a photonic lantern

Photonic lanterns can sense aberrations at the science imaging plane

Potential for minimally invasive upgrades to existing AO systems

Abstract

Ground-based direct imaging of exoplanets at high contrast requires precise correction of atmospheric turbulence using adaptive optics (AO). The planet-to-star contrast ratio at small angular separations from the host star is often limited by non-common-path aberrations (NCPAs) seen only in the science plane. The photonic lantern (PL) can be used to sense aberrations at the final science imaging plane. This enables a two-stage wavefront control architecture, in which the first-stage wavefront sensor senses atmospheric turbulence and the PL senses NCPAs and other aberrations not seen by the first stage. We demonstrate closed-loop control of residual wavefront errors using a non-dispersed PL after first-stage AO correction on the Shane 3m telescope at Lick Observatory. Our results show that non-dispersed PLs can be used for second-stage wavefront sensing, enabling performance improvements via minimally invasive retrofits to existing AO systems.