title: Separate and simultaneous investigation of absorption gratings and refractive-index gratings by beam-coupling analysis: comment.
abstract: We correct a fundamental error occurring in the paper by F. Kahmann [J. Opt. Soc. Am. A10, 1562 (1993)] leading to a different value for the parameter varphi(p,0), i.e., the initial phase shift for the complex grating.
authors.affiliation: Nonlinear Physics Group, Faculty of Physics, Universität Wien, Austria. martin.fally@univie.ac.at
authors.forename: Martin
authors.initials: M
authors.lastname: Fally