Transverse Anderson localization of surface plasmon polaritons

We investigate the effect of disorder on the propagation of surface plasmon polaritons in arrays of evanescently coupled dielectric loaded surface plasmon polariton waveguides. Diagonal disorder is implemented by randomly varying the heights of the waveguides. Real-space as well as Fourier-space images of the surface plasmon polariton intensity distribution in the waveguide arrays are recorded by leakage radiation microscopy. With these techniques we experimentally demonstrate the transverse localization of surface plasmon polaritons with increasing disorder.