Measuring and correcting atmospheric turbulence through Quantum-Inspired Imaging (QI2)

Our team has recently demonstrated a photonic Quantum-Inspired Imager (QI2) which provides source reconstruction below the optical/NIR diffraction limit in the presence of atmospheric turbulence without the need for adaptive optics. Turbulent cells in the atmosphere reduce image resolution by causing fluctuations in the phase of propagating wavefronts. Rather than relying on conventional methods of wavefront sensing, our approach leverages the spectral diversity inherent in the factors which limit resolution, thus breaking the degeneracy between these aberrating processes. Though this concept has long been employed in astronomy to achieve diffraction limited imaging, our approach achieves this necessary spectral diversity with a passive photonic lantern mode multiplexer that converts a multimode wavefront input into an array of spatially distinct single-mode outputs, from which we can deduce the atmospheric phase variations and reconstruct the source function. We present detailed simulations, laboratory tests, and on-sky results demonstrating the effectiveness of the QI2 approach in measuring atmospheric turbulence and correcting phase distortions.