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.
© 2003 Optical Society of America
(050.0050) Diffraction and gratings : Diffraction and gratings
(050.1940) Diffraction and gratings : Diffraction
(050.1950) Diffraction and gratings : Diffraction gratings
(050.2770) Diffraction and gratings : Gratings
(310.0310) Thin films : Thin films
Hongbo Wei and Lifeng Li, "All-Dielectric Reflection Gratings: A Study of the Physical Mechanism for Achieving High Efficiency," Appl. Opt. 42, 6255-6260 (2003)