Non-destructive splitter of twisted light

TL;DR

This paper presents a non-destructive method using a ring cavity with Dove prisms to effectively split beams carrying different orbital angular momentum, enabling high-efficiency, selective separation for optical and quantum applications.

Contribution

The authors introduce a novel cavity-based technique with Dove prisms for non-destructive, high-efficiency splitting of OAM beams, including multi-OAM modes, verified experimentally.

Findings

Splitting efficiency can reach unity with lossless cavity and perfect mode matching.

The method allows selective transmission of a chosen OAM beam without destroying its spatial structure.

Cascading cavities can split beams carrying multiple OAMs effectively.

Abstract

Efficiently discriminating beams carrying different orbital angular momentum (OAM) is of fundamental importance for various applications including high capacity optical communication and quantum information processing. We design and experimentally verify a distinguished method for effectively splitting different OAM-carried beams by introducing Dove prisms in a ring cavity. Because of rotational symmetry broken of two OAM-carried beams with opposite topological charges, their transmission spectra will split. When mode and impedance matches between the cavity and one OAM-carried beam are achieved, this beam will transmit through the cavity, and other beam will be reflected without being destroyed their spatial shapes. In this case, the cavity acts like a polarized beam splitter. The transmitting beam can be selected at your will. The splitting efficiency can reach unity if the cavity is lossless and it completely matches with the beam. Beams carry multi-OAMs can also be effectively split by cascading ring cavities.