  Despite recent tremendous progress in optical imaging and metrology, the
resolution gap between atomic scale transmission electron microscopy and
optical techniques has not been closed. Is optical imaging and metrology of
nanostructures exhibiting Brownian motion possible with resolution beyond
thermal fluctuations? Here we report on an experiment in which the average
position of a nanowire with a thermal oscillation amplitude of ~150 pm is
resolved in single-shot measurements with precision of 92 pm using light at a
wavelength of {\lambda} = 488 nm, providing the first example of such
sub-Brownian metrology with ~{\lambda}/5,300 precision. To localize the
nanowire, we employ a deep learning analysis of the scattering of topologically
structured light, which is highly sensitive to the nanowire's position. As a
non-invasive optical metrology with sub-Brownian absolute errors, down to a
fraction of the typical size of an atom (Si: 220 pm diameter), it opens the
exciting field of picophotonics.
