title: All-dielectric reflection gratings: a study of the physical mechanism for achieving high efficiency.
abstract: The physical mechanism for the all-dielectric reflection gratings to achieve high efficiency in the -1st-order Littrow mounting is studied. The all-dielectric gratings consist of two parts, a surface-relief grating and a highly reflecting dielectric stack. The surface-relief grating sits on top of the reflecting stack. A simple analytical expression for diffraction efficiency is obtained in terms of the S-matrix elements of the two parts. By analyzing the expression we show that the diffraction can be interpreted as the interference of a symmetric wave and an antisymmetric wave. The conditions for achieving high diffraction efficiency are also identified. The analytical results are illustrated by numerical computations.
authors.affiliation: Department of Precision Instruments, Tsinghua University, Beijing 100084, China.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Wei
authors.forename: Lifeng
authors.initials: L
authors.lastname: Li