Wide viewing angle skewed effect of the point spread function in a wavefront coding system.

The point spread function (PSF) of a wavefront coding (WFC) system with a cubic phase mask is analyzed with a wide viewing angle based on physical optics for what is believed to be the first time. Two coordinate transformations are made to generate a pupil function, from which we obtain the encoded PSF of the NATC system with defocus parameters W-020 and object angles alpha and beta. The encoded PSFs are further side extended as the object angles get wider. When alpha beta < 0, the included angle Phi of encoded PSF will skew to an obtuse angle. When alpha beta = 0, Phi remains orthogonal; when alpha beta > 0, Phi will skew to an acute angle. Furthermore, the effect of skew and side extension is even symmetric about W-020. As a result, the wide viewing angle has a bad effect on the imaging quality of the WFC system. (c) 2007 Optical Society of America.