title: Achromatic combinations of hologram optical elements.
abstract: Two- and three-element combinations of hologram optical elements are considered, and analytical conditions are obtained for absence of longitudinal dispersion. Solutions of the conditional equations are compared with another author's computed design results. A simple doublet design is considered for an eyepiece, and its performance is described.
authors.forename: S J
authors.initials: SJ
authors.lastname: Bennett