Trapping of surface-plasmon polaritons in a subwavelength cut

We study a transverse magnetic wave propagation in a subwavelength metallic slit which is modified by a perpendicular cut. The surface-plasmon polaritons (SPPs) can be trapped in the perpendicular cut by tuning the length or width of the cut. Moreover, the period of the resonance states corresponds to the difference of the cut's length Delta L which is 450 nm. An analytical solution for the resonance condition of the structure is derived by the cavity theory, which is consistent with the numerical simulation by using the finite difference time domain (FDTD) method. (C) 2010 Elsevier B.V. All rights reserved.