A special model of a thin transmission grating used to couple infrared radiation to electronic excitations in quantum wells is examined. The grating is viewed as a periodic array of two-dimensional (2D) conducting strips separated by completely open apertures. The 2D conductivity across each strip has a semielliptic profile. This simple functional form allows considerable analytic progress. We examine both the recent approximation scheme proposed by Mikhailov for this class of grating and more complete theories. By physical arguments and numerical examples we show that Mikhailov’s approximation can work very well, but that it is also rather easy to correct for its small errors.

• Received 14 January 2000

DOI:https://doi.org/10.1103/PhysRevB.62.2721