Theoretical research on the novel adaptive optics configuration based on the tubular deformable mirror for the aberration correction of the annular laser beam

The annular laser beam (ALB) has been widely used in many fields for its unique intensity distribution. Especially, in the materials processing, the power and the beam quality of the large-aperture thin-wall ALB are of vital. However, limited by the aperture, the actuators' spacing or the damage threshold, the existing deformable mirrors (DMs) are not suitable for the correction of the ALB. Considering the stretching effect of the oblique incidence, in this paper, by using the tubular DM (TDM), a novel adaptive optics (AO) configuration is promoted to increase the number of the effective actuators covered by the input ALB. The coordinate transformation equations and correction principle of the novel AO configuration are derived based on the ray tracing. A typical TDM prototype is designed based on the coordinate transformation equations. The influence function characteristics of the TDM is analyzed using the finite element method, and the correction ability of the novel AO configuration based on the TDM is verified. Simulation results show that the TDM could perfectly compensate the wavefront distortions described by the 2th to 15th order Zernike annular aberrations.