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arXiv · 2405.09065

Optimal beam displacement measurements using high-order structured light modes

A. L. S. Santos Junior·J. C. de Carvalho Junior·M. Gil de Oliveira·E. V. S. Cubas·R. F. Barros·A. Z. Khoury·G. B. Alves
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Abstract

We develop a novel technique to measure small angular and lateral displacements of structured light beams. The technique relies on using high-order Hermite-Gaussian (HG) and Laguerre-Gaussian (LG) modes, which have well-defined symmetry under inversion. We show that the displacements of such fields lead to a crosstalk with modes with opposite parity under inversion, which we measure optimally with an interferometric parity sorter. Using this technique, we achieve improvement factors of up 41 in the signal-to-noise ratio using Hermite-Gaussian modes and 21 using Laguerre-Gaussian modes with order up to 20, as compared to the fundamental Gaussian mode. Our results present a viable way of using structured light for metrology that does not demand quantum light or homodyne detection.

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A. L. S. Santos Junior, J. C. de Carvalho Junior, M. Gil de Oliveira, E. V. S. Cubas, R. F. Barros, A. Z. Khoury, G. B. Alves. 2024-05-15. Optimal beam displacement measurements using high-order structured light modes. https://arxiv.org/abs/2405.09065

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