Strong discontinuities in the complex photonic band structure of transmission metallic gratings - art. no. 033107

Complex photonic band structures (CPBS) of transmission metallic gratings w ith rectangular slits are shown to exhibit strong discontinuities that are not evidenced in the usual energetic band structures. These discontinuities are located on Wood-Rayleigh's anomalies and reveal unambiguously two diff erent types of resonances, which are identified as horizontal and vertical surface-plasmon resonances. Spectral position and width of peaks in the tra nsmission spectrum can be directly extracted from CPBS for both kinds of re sonances.