Delocalized waves in one-dimensional disordered layered systems with oblique incidence

In this paper, we present disordered layered systems in which delocalized waves with nonzero frequency can exist in the case of oblique incidence. The appearance of the delocalized waves is attributed to two factors: one is the existence of the localized modes in the systems, and the other is the phase matching condition. The conclusions are not in agreement with the traditional view, and may provide new understanding to the wave phenomena in one-dimensional disordered systems. In addition, the systems proposed here are also very useful for detecting and generating quasi-monochromatic acoustic waves.