Atlas observes light scattering off light
Light by light scattering was first observed at SLAC in the mid 90s by experiment E-144.<p><a href="https://physicsworld.com/a/light-is-seen-to-scatter-off-light/" rel="nofollow">https://physicsworld.com/a/light-is-seen-to-scatter-off-ligh...</a><p>Link to paper from 1997:
Positron Production in Multiphoton Light-by-Light Scattering<p>(published in Phys. Rev. Lett., Vol. 79, p. 1626 (1997).)
<a href="http://www.slac.stanford.edu/exp/e144/ps/positron_slacpub.ps" rel="nofollow">http://www.slac.stanford.edu/exp/e144/ps/positron_slacpub.ps</a>