Superposition of two fractional optical vortices and the orbital angular momentum measurement by a deep-learning method

Abstract

We propose a single diffractive optical element called the composite fractional spiral zone plates to generate superimposed fractional optical vortices. Such an element is composed of two fractional spiral zone plates (FSZPs) through logical AND operation, and the produced beam carries superimposed fractional orbital angular momentum (OAM) states. By controlling the topological charge of the superimposed FSZPs, denoted by l 1 and l 2 , one can flexibly obtain the desired superimposed fractional OAM modes of the generated beam. Especially, a deep-learning model with a densely connected convolutional neural network architecture is utilized to accurately predict the superimposed fractional OAM states of SFOVs. The average recovery rate of the superimposed fractional OAM states based on the training model is over 99%, and the average error is as small as 0.02. This work may pave the way for wide-ranging applications such as smart OAM communication, particle transmission, and even quantum entanglement.

Machine-learning-assisted orbital angular momentum recognition using nanostructures

“…This ability makes the intricate task of separating and decoding the interwoven OAM channels manageable. AI-powered OAM demultiplexing techniques can also recognize complex light patterns like fractional vortex [18] beams and partially coherent [19] vortex beams even in the presence of atmospheric turbulence. Integrating AI into this process not only boosts the effectiveness of data management but also lays the groundwork for developing more complex and secure communication frameworks.…”

High-Resolution Recognition of Orbital Angular Momentum Modes in Asymmetric Bessel Beams Assisted by Deep Learning

“…Notably, these scenarios encompass free-space optical communication, [29][30][31] mitigation of atmospheric turbulence effects, [32,33] and analyses of various fractional vortex beams. [34,35] In the preceding investigations, applications of fractional OAM modes have met challenges of propagation instability. This instability has constrained the measurement of fractional OAM to predetermined distances, thereby introducing potential complications for communication endeavors.…”