Design and experimental validation of an aspheric multi-lenticular plano-convex lens for VCSEL beam collimation

In this work, we propose a design method of an aspheric lens that achieves collimation for a VCSEL laser beam. The designed lens features a planar front surface and an aspheric back surface of which the profile is mathematically characterized and precisely determined based on the proposed method. The method is derived from a basic geometric-optics analysis and construction approach. The collimating effect of the lens was first analyzed in simulation and then validated in experimental measurement. The experimental results show that the collimator lens transforms the input VCSEL laser beam divergence angle from 25° (436.33 mrad) to an output angle of 3.6906 mrad.