On-demand measurement of higher topological charges using Hadamard-coded apertures with a DMD

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外文摘要：© 2022 Elsevier GmbHThe diffraction of an orbital angular momentum (OAM) beam behind slits and polygon apertures has enabled the measurement of light's topological charge (TC). In this work, we present a simple technique to measure higher TCs using Hadamard-coded apertures programmed in a digital micromirror device (DMD). Apart from pattern recognition, a common approach in relating the topological properties of the beam with its diffraction, we demonstrate that we can determine TCs from m=±1 to ±10 using the position of diffracted intensity centroid R. We show thru experiments and simulations that indeed the centroids of the diffracted beams move depending on the magnitude and the sign of the TC, and the order N of the Hadamard aperture. Based on our results, distinguishing the TC of a beam is easier when |m|>5. Lastly, we infer the source of the movement of the centroid using simple interference of three points derived from a Hadamard N = 2. By tracing the position of the zeroth-order maxima in the interference, we relate the maximum intensity position with the intensity centroid position in the diffraction. Our technique is crucial for determining higher-order modes whose TC are difficult to determine with the currently available methods.

外文关键词：

DiffractionHadamard matrixIntensity centroidOrbital angular momentum

作者：

Banguilan D.G.C.、Estrada V.G.、Hermosa N.P.

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作者单位：

National Institute of Physics College of Science University of the Philippines

出版年：

2022

DOI：

10.1016/j.ijleo.2022.169260

Optik

EISCI

ISSN：0030-4026

年,卷(期)：2022.262

参考文献量46