title: Focal depth: optimum annular apodizer.
abstract: We discuss an annular apodizer that minimizes the second moment of the Strehl ratio vs defocus for a prespecified light gathering power.
authors.forename: J
authors.initials: J
authors.lastname: Ojeda-Castaneda
authors.forename: C M
authors.initials: CM
authors.lastname: Gomez-Sarabia