H. Kudo and S. Komatsu : Comparison of characteristics between cubic phase mask and free-form phase mask for wavefront coding, Technical Digest, MOC'09 (Odaiba, Tokyo, 2009), 154-155 (2009). (J-15)

A series of performance comparisons between the free-form phase mask (FPM) and the cubic phase mask (CPM) in extending the depth of field are carried out by arranging the thickness of the phase mask. Computer simulation results show that the FPM provides an advantage over the CPM in several aspects.