Nondestructive Separation Method and Separation Subsystem for Arbitrarily Multiplexed Orbital Angular Momentum States

Abstract

The invention discloses a non-damage separating method and separating subsystems of random multiplex rail angular momentum states. By the aid of the light polarization property, the non-damage separation of random multiplex rail angular momentum states is achieved by cascading the multiple multiplex rail angular momentum state separating subsystems. For each subsystem, each rail angular momentum state in the input multiplex states can be projected to two horizontal or perpendicular polarity directions according to phase characteristics of itself after being subjected to a series of polarization operation. By cascading n layers of multiplex rail angular momentum state separation subsystems, non-damage separation of 2n rail angular momentum state multiple light beams can be achieved. By means of the separation method, on one hand, a good separation effect is achieved, no damage can be caused to the space structure of rail angular momentum states; on the other hand, optical devices required in the separation process are not complex, are easy to manufacture and have good compatibility and applicability for the existing optical communication technology.

Description

technical field [0001] The invention relates to a method for non-destructive separation of arbitrary multiplexed orbital angular momentum states, which belongs to the technical field of optics and wireless communication. Background technique [0002] Photon is an important carrier of information transmission, and the energy, linear momentum and polarization state of photon can be used as degrees of freedom to carry information. Like other degrees of freedom, the angular momentum of photon has also been proved to be a new type of information carrier in recent years. Angular momentum is divided into two types: spin angular momentum (English name is spin angular momentum, abbreviated as SAM) and orbital angular momentum (English name is orbit angular momentum, abbreviated as OAM), in which spin angular momentum is related to the polarization of photons , which is related to polarization; while the orbital angular momentum is related to the spatial distribution of photons. In ...

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Problems solved by technology

However, when using this method to separate more OAM states, the system structure will be very complicated, and the realization of the Mach-Zehnder interference process is more complicated

In 2010, Martin P.J.Lavery et al. proposed a new method for efficiently separating OAM states. Based on the principle of static optics, the coordinate transformation is used to convert the spiral phase beam into a transverse phase gradient light, and then through the lens to separate each OAM state. The light of the state can be focused to different lateral positions to distinguish different OAM states, but the implementation still requires the use of expensive equipment—spatial light modulator, and the spatial structure of the OAM state will be destroyed after the separation is completed.

In 2014, Lixiang Chen et al. proposed a method for separating orbital angular momentum states based on the polarization properties of light. The implementation structure of this method is still relatively complicated, and it does not give the separation of multiplexed OAM states with opposite topological charges (ie, +l and -l multiplexed OAM state) specific scheme

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