  With increasing interest in using orbital angular momentum (OAM) modes in
high-power laser systems, accurate mathematical descriptions of the
high-intensity modes at focus are required for realistic modelling. In this
work, we derive various high intensity orbital angular momentum focal spot
intensity distributions generated by Gaussian, super-Gaussian, and ideal
flat-top beams common to high-power laser systems. These intensity
distributions are then approximated using fitted Laguerre-Gaussian basis
functions as a practical way for describing high-power OAM beams in theoretical
and numerical models.
