Limits of imaging-system simplification using cubic mask wavefront coding.

Increasing the space-bandwidth product of an imaging system will lead to a complex and expensive optical system. Techniques exist to simplify imaging systems. We propose the use of a hybrid imaging system using pupil phase modulation. Based on the reconstructed image's mean-squared error, we compute how this error is affected under various third-order aberrations. We determine the best cubic phase-mask parameter and study the impact of the orientation of the coma and astigmatism, as we have in a real optical system (from 0 to 2π). We then compute how the reconstructed image's quality varies by adding defocus-related aberrations (defocus and/or field curvature). Based on our analysis, we determine the limits of a hybrid imaging system using a cubic phase mask to develop simplified imaging systems. We conclude that the simplified lens design can be corrected if its aberrations are limited to 1 lambda of coma, astigmatism, and spherical aberrations and less than 1 lambda of field curvature or defocus.