摘要： We compare the performance in term of accuracy and convergence of numerical modal methods as applied to photonic and plasmonic structures. Both pure spectral problems and diffraction problems are investigated. The main challenge of any numerical modal method is to handle at best the interface conditions at the boundary of the different materials that constitute the structure and also radiation conditions in the case of isolated structures. That is the reason why we distinguish two kinds of modal methods according to whether they use full-domain or sub-domain basis expansion. In the ?rst set we will consider the Fourier Modal Method, the B-spline modal methods, and in the second one Pseudo-Spectral modal methods and Polynomial modal methods.