Orbital angular momentum splitter of light based on beam displacer

Abstract

In recent years, the high dimensional properties of the orbital angular momentum degree of freedom of light have attracted extensive attention. This degree of freedom has been studied and applied in many scientific fields, especially in optical communication and quantum information. In order to give full play to the high dimensional characteristics of orbital angular momentum, it is a basic requirement to separate different orbital angular momentum states without destruction. However, the existing orbital angular momentum beam-splitting systems either lack in stability and cascade expansibility. Either the orbital angular momentum after separation is severely damaged and cannot participate in further interaction processes. In this paper, we construct a miniature Mach-Zehnder interferometer based on the beam displacer, realize the non-destructive beam splitting of orbital angular momentum mode, and design an orbital angular momentum beam splitter. In the orbital angular momentum splitter designed by us, the theoretical energy loss is zero because there is only total reflection of the beam. The beam in the miniature Mach-Zehnder interferometer passes through the same optical element, and the spatial deviation of the beam is small, so the orbital angular momentum beam splitter has good stability. In addition, because the separated orbital angular momentum state has the same propagation direction as the incident orbital angular momentum state, the beam splitter has good extensibility and is easy to be used in cascade. Our research is of great significance to the application of orbital angular momentum as a high dimensional degree of freedom in optical communication and other related fields.