title: Image-scaling problem in the optical fractional Fourier transform.
abstract: The significance of scale factors and cascade of optical fractional Fourier transform is emphasized. Exact and cascadable fractional Fourier transforms in practical applications mandate that the image scale be the reciprocal of the scale of the input plane controlled by the optical setup. The practical setup of the optical fractional Fourier transform must be without any quadratic phase term at the spectrum plane.
authors.forename: S
authors.initials: S
authors.lastname: Liu
authors.forename: H
authors.initials: H
authors.lastname: Ren
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: X
authors.initials: X
authors.lastname: Zhang