  In this work, we present a novel and practical method for generating optical
vortices in high-power laser systems. Off-axis spiral phase mirrors are used at
oblique angles of incidence in the beam path after amplification and
compression allowing for the generation of high-power optical vortices in
almost any laser system. An off-axis configuration is possible via modification
of the azimuthal gradient of the spiral phase helix and is demonstrated with a
simple model using a discrete spiral staircase. This work presents the design,
fabrication, and implementation of off-axis spiral phase mirrors in both low
and high-power laser systems.
