We discuss asymmetric reflectance in surface plasmon Bragg gratings incorporating optical gain, referred to as active asymmetric surface plasmon Bragg gratings. It is shown that balanced modulation of index and gain/loss with quarter pitch spatial shift causes unidirectional coupling between contra-propagating modes in long-range surface plasmon polariton Bragg gratings. Such gratings operate at the breaking threshold of parity-time symmetry (exceptional point). Two active asymmetric surface plasmon Bragg gratings designs are proposed and their performance is examined through modal and transfer matrix method computations.

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Persistent URL dx.doi.org/10.1117/12.2238704
Conference Active Photonic Materials VIII
Karami Keshmarzi, E. (Elham), Hahn, C. (Choloong), Song, S.H. (Seok Ho), Oh, C.H. (Cha Hwan), Tait, R, & Berini, P. (Pierre). (2016). Active asymmetric plasmonic Bragg gratings. In Proceedings of SPIE - The International Society for Optical Engineering. doi:10.1117/12.2238704