Design of highly efficient far-field beam shapers with irregular maskless microlens arrays.

Regular tandem microlens arrays are well described and widely used for beam shaping and homogenization. Applying absorbing slides between the entrance and exit lenslets and channel-wise variation of the slides' shape and size allows flexible control of the beam's intensity profile and silhouette. The downside of absorbing slides is a significant transmission loss, limiting the achievable level of system efficiency. This work describes a more efficient method for micro-optical beam shaping with maskless irregular microlens arrays (iMLA). The iMLAs are completely absorption-free elements, enhancing the overall efficiency of the optical system. We describe basic design rules for iMLAs, including stray-light suppression, tolerancing, and modeling under consideration of manufacturing imperfections.