title: Circularly symmetric phase filters for control of primary third-order aberrations: coma and astigmatism.
abstract: A quartic phase retardation function is described that reduces the variation of the intensity of the focal point of incoherent imaging systems suffering from primary third-order aberrations limited to coma and astigmatism. Corresponding modulation transfer functions are shown to remain practically invariant for moderate amounts of coma and astigmatism.
authors.affiliation: Displays and Optical Technology Group, Visteon Customer and Technology Centre, Basildon, Essex, UK.
authors.forename: Samir
authors.initials: S
authors.lastname: Mezouari
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Muyo
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Harvey