Analysis of divergence angles of truncated and untruncated beams in collimation system

Abstract This research is performed to evaluate the divergence angle of far-field distribution of the collimation system. A concise method that can analyze the divergence performance of a collimation system is put forward. Simulation methods for beam truncated systems and beam untruncated systems are proposed. For truncated beams, a proper parabolic distribution at z = 0 is used to approximate the beam with “bell-shaped” EFD (equivalent field distribution). Results show that the flat-top beam ( h = 1 ) has the minimal divergence angle. The parabolic function is easier to process than the Gaussian function. For untruncated beams, the calculation results indicate that the Lorentzian beam has a minimum divergence angle. It is foreseeable that this study will play a positive role in driving the design and evaluation of the collimation system.