Abstract

An acoustooptic two-pupil heterodyne scanning system has been proposed to overcome the constraints in a conventional incoherent optical systems.¹,² We investigate the defocusing image effect on the optical transfer function (OTF) of the two-pupil system. We first show that the OTF of the defocused system can be expressed by the cross ambiguity of the two pupil functions. Next, we take two offset pupil functions both having Gaussian shape and obtain the OTF of the defocused system. It is shown that the OTF in this particular case is a bandpass filtering function. As the defocusing distance increases, the center spatial frequency corresponding to the OTF peak value moves from the high-frequency range to the low-frequency range. Experimental results are presented. Finally, we discuss the system's potential use in 3-D processing.

© 1988 Optical Society of America