Calculation of the average lenslet shape and aberrations of microlens arrays from their far-field intensity...

We present a method to obtain the average lenslet shape of microlens arrays and especially their aberrations from the far-field intensity distribution of the whole array. The method is based on the phase-retrieval algorithm introduced by Gerchberg and Saxton [Optik (Stuttgart) 35, 237 (1972)]. We show how to overcome the crucial point of this algorithm, that is finding suitable start parameters to end up with correct results. The procedure is successfully applied to a cylindrical microlens array produced by reflow technique and the result is compared with surface profilometric measurements. The technique is applicable for lenslets having small numerical apertures and fill factors near unity.