Anderson localization of surface plasmon polaritons in engineered disorder

In this work, we experimentally demonstrate Anderson localization of surface plasmon polaritons (SPPs) at visible regime in metallic nanogratings with short-range correlated disorder. By increasing the degree of disorder, the confinement of SPPs is significantly enhanced, and the effective SPP propagation length dramatically shrinks. Strong localization of SPPs eventually emerges at visible regime, which is verified by the exponentially decayed fields and the vanishing autocorrelation function of the SPPs. Physically, the short-range correlated disorder induces strong interference among multiple scattered SPPs and provides an adequate fluctuation to effective permittivity, which leads to the localization effect. Our study demonstrates a unique opportunity for disorder engineering to manipulate light on nanoscale and may achieve various applications in random nanolasing, solar energy, and strong light-matter interactions. Reference: W. Shi, L. Liu, Ruwen Peng, D. Xu, K. Zhang, H. Jing, R. H. Fan, Xian-Rong Huang, Q. Wang, and Mu Wang, Nano Letters 18, 1896-1902 (2018).