Photoconducting film integrated in a magnetooptical multilayer structure: a new way to get bistable and unstable operations

TE/TM polarized light reflection from a multilayer structure containing a magnetooptic and a photoconducting film is investigated theoretically. A metal film whose thickness is chosen to support long-range surface plasmons is used. Their sharp resonance is used for tuning the whole structure. The off-diagonal elements of the dielectric tensor are ∈₁₂=∈₂₁=ig and these can be switched from g =0.05 to g=-0.05. Light tunneling in the photoconducting layer causes the appearance of a current that can reorient the magnetization from M to -M (g=-0.05). The switching occurs at 0.5 mW given an initial value g=0.05. The back reorientation -M→ M, as the light intensity is reduced, occurs at only 0.1 mW. Hence it is shown that TE reflected light will exhibit a novel bistable dependence