Evaluation of optical systems using the dynamic properties of laser-produced speckles

A lens-evaluation method based on the dynamic properties of laser-produced speckles is investigated and developed into a real-time modulation-transfer-function measuring system controlled by a microprocessor. One of the most important advantages of this method is the redundancy that permits rough adjustment of the lateral position of the light detecting point in the focal plane. Experimental results applied to a grin-rod lens as well as to an ordinary camera lens are obtained. For detection of the best focal position, the method of counting the zero-cross distribution along the optical axis is found to be effective.