title: Negative index modes in surface plasmon waveguides: a study of the relations between lossless and lossy cases.
abstract: Surface plasmon modes in structures of metal-insulator-metal (MIM), insulator-insulator-metal (IIM) and insulator-metal-insulator (IMI) are studied theoretically for both lossless and lossy cases. Causality dictates which solutions of Maxwell's equations we accept for these structures. We find that for both lossless and lossy cases, the negative index modes and positive index modes are independent and should be treated separately. For the lossless case, our results differ from some published papers. By studying in detail the lossy case, we demonstrate how the curves should look like.
authors.affiliation: Institute of Optoelectronic Materials and Technology, South China Normal University, Guangzhou 510631, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xuejin
authors.initials: X
authors.lastname: Zhang
authors.forename: Ting
authors.initials: T
authors.lastname: Mei
authors.forename: Michael
authors.initials: M
authors.lastname: Fiddy