Influence of misfit strain on the Goos–Hänchen shift upon reflection from a magnetic film on a nonmagnetic substrate

International audienceThe influence of the misfit strain on the lateral shift (Goos–Hänchen effect) experienced by a near-infraredelectromagnetic wave upon reflection from the surface of a bilayer consisting of a magnetic, gyrotropic (i.e., whosepermittivity tensor elements depend upon magnetization) yttrium–iron garnet film deposited on a nonmagneticgadolinium–gallium garnet substrate is investigated theoretically. In the geometry of the transverse magnetoopticalKerr effect, it is shown that the mechanical strain near the geometrical film/substrate interface can inducea significant lateral shift of the beam for incidence angles close to normal incidence, where no shift appears in theabsence of strain. Our calculations demonstrate positive as well as negative values of the lateral shift, depending onthe incident light polarization and on the film thickness. In contrast with that of the misfit strain, the influence ofthe magnetization of the gyrotropic film on the lateral shift is more noticeable for a TM- than for a TE-polarizedwave