title: Design and application of a bifocus lens.
abstract: A method of designing a bifocus lens is presented. The authors explain how to use the ray-tracing formulas that were suggested in a previous paper [Appl. Opt. 31, 7328 (1992)]. The method of calculating physical quantities in formulas and sign rules is also presented. This method can also be applied to the design of other crystal elements. One useful application of a bifocus lens is as a bifocus interference surface profilometer.
authors.forename: W Q
authors.initials: WQ
authors.lastname: Zhang
authors.forename: Y M
authors.initials: YM
authors.lastname: Zhuo