Wavefront coding is a powerful technique that can be used to extend the depth of field of an incoherent imaging system. By adding a suitable phase mask to the aperture plane, the optical transfer function of a conventional imaging system can be made defocus invariant. Since 1995, when a cubic phase mask was first suggested, many kinds of phase masks have been proposed to achieve the goal of depth extension. In this Letter, a phase mask based on sinusoidal function is designed to enrich the family of phase masks. Numerical evaluation demonstrates that the proposed mask is not only less sensitive to focus errors than cubic, exponential, and modified logarithmic masks are, but it also has a smaller point-spread-function shifting effect.
© 2010 Optical Society of America
Original Manuscript: August 26, 2009
Revised Manuscript: November 16, 2009
Manuscript Accepted: November 24, 2009
Published: January 15, 2010
Hui Zhao and Yingcai Li, "Optimized sinusoidal phase mask to extend the depth of field of an incoherent imaging system," Opt. Lett. 35, 267-269 (2010)