An all-photonic focal-plane wavefront sensor. (arXiv:2003.05158v1 [astro-ph.IM])
<a href="http://arxiv.org/find/astro-ph/1/au:+Norris_B/0/1/0/all/0/1">Barnaby R. M. Norris</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wei_J/0/1/0/all/0/1">Jin Wei</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Betters_C/0/1/0/all/0/1">Christopher H. Betters</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wong_A/0/1/0/all/0/1">Alison Wong</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leon_Saval_S/0/1/0/all/0/1">Sergio G. Leon-Saval</a>
Adaptive optics (AO) is critical in modern astronomy, as well as in optical
communications and remote sensing, to deal with the rapid blurring caused by
the Earth’s turbulent atmosphere. But even the best AO systems are limited by
their wavefront sensors, which need to be in an optical plane non-common to the
science image, unavoidably leading to errors that limit the reach of current
astronomy. They are also insensitive to certain wavefront-error modes, and are
poorly suited to injecting light into single-mode optical fibres, important for
applications such as high-resolution spectroscopy of extra-solar planets. Here
we present a new type of wavefront sensor based on a photonic lantern
fibre-mode-converter and deep learning. This new wavefront sensor can be placed
at the same focal plane as the science image, and is also optimal for
single-mode fibre injection. By only measuring the intensities of an array of
single-mode outputs, both phase and amplitude information on the incident
wavefront can be reconstructed. We demonstrate the concept with both
simulations and an experimental realisation of this novel wavefront sensor,
wherein Zernike wavefront errors are recovered from focal-plane measurements to
a precision of $2.6times10^{-5}$ radians mean-squared-error.
Adaptive optics (AO) is critical in modern astronomy, as well as in optical
communications and remote sensing, to deal with the rapid blurring caused by
the Earth’s turbulent atmosphere. But even the best AO systems are limited by
their wavefront sensors, which need to be in an optical plane non-common to the
science image, unavoidably leading to errors that limit the reach of current
astronomy. They are also insensitive to certain wavefront-error modes, and are
poorly suited to injecting light into single-mode optical fibres, important for
applications such as high-resolution spectroscopy of extra-solar planets. Here
we present a new type of wavefront sensor based on a photonic lantern
fibre-mode-converter and deep learning. This new wavefront sensor can be placed
at the same focal plane as the science image, and is also optimal for
single-mode fibre injection. By only measuring the intensities of an array of
single-mode outputs, both phase and amplitude information on the incident
wavefront can be reconstructed. We demonstrate the concept with both
simulations and an experimental realisation of this novel wavefront sensor,
wherein Zernike wavefront errors are recovered from focal-plane measurements to
a precision of $2.6times10^{-5}$ radians mean-squared-error.
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