Theory of grating-coupler-assisted infrared spectroscopy of lower-dimensional electron systems: Local optics of anisotropic multilayer systems with grating

A new matrix method is developed, based on both the transfer-matrix techniq ue and the modal-expansion method, for calculating the optical properties o f multilayer systems of anisotropic media with grating coupler. Using this theory it is possible to calculate the transmission and reflection coeffici ent, the electromagnetic field distributions, and the dispersion relations of virtual modes. It is shown that the obtained results are identical with that using the scattering-matrix technique. Detailed numerical results are presented for GaAs-Ga1-xAlxAs heterostructures with a silver grating on top of the sample. Special attention is directed to the effects of both the ty pes of Wood's anomalies on the optical spectra. (C) 1999 Elsevier Science B .V. All rights reserved.