{"publication_identifier":{"eissn":["2515-7647"]},"file":[{"access_level":"open_access","file_id":"21476","relation":"main_file","file_name":"2026_JPhysPhotonics_Bahl.pdf","content_type":"application/pdf","date_created":"2026-03-23T13:24:01Z","checksum":"0ec8a2d3f9efa704203a41f068344974","date_updated":"2026-03-23T13:24:01Z","creator":"dernst","success":1,"file_size":1150404}],"project":[{"name":"Coherent Optical Metrology Beyond Electric-Dipole-Allowed Transitions","grant_number":"F100403","_id":"7c040762-9f16-11ee-852c-dd79eeee4ab3"}],"date_published":"2026-03-10T00:00:00Z","scopus_import":"1","citation":{"ista":"Bahl M, Koutentakis G, Maslov M, Jungnickel T, Gaßen T, Lemeshko M, Heckl OH. 2026. The R-index: A universal metric for evaluating OAM content and mode purity in optical fields. Journal of Physics: Photonics. 8(1), 015071.","short":"M. Bahl, G. Koutentakis, M. Maslov, T. Jungnickel, T. Gaßen, M. Lemeshko, O.H. Heckl, Journal of Physics: Photonics 8 (2026).","ama":"Bahl M, Koutentakis G, Maslov M, et al. The R-index: A universal metric for evaluating OAM content and mode purity in optical fields. <i>Journal of Physics: Photonics</i>. 2026;8(1). doi:<a href=\"https://doi.org/10.1088/2515-7647/ae3506\">10.1088/2515-7647/ae3506</a>","chicago":"Bahl, Monika, Georgios Koutentakis, Mikhail Maslov, Tom Jungnickel, Timo Gaßen, Mikhail Lemeshko, and Oliver H. Heckl. “The R-Index: A Universal Metric for Evaluating OAM Content and Mode Purity in Optical Fields.” <i>Journal of Physics: Photonics</i>. IOP Publishing, 2026. <a href=\"https://doi.org/10.1088/2515-7647/ae3506\">https://doi.org/10.1088/2515-7647/ae3506</a>.","ieee":"M. Bahl <i>et al.</i>, “The R-index: A universal metric for evaluating OAM content and mode purity in optical fields,” <i>Journal of Physics: Photonics</i>, vol. 8, no. 1. IOP Publishing, 2026.","apa":"Bahl, M., Koutentakis, G., Maslov, M., Jungnickel, T., Gaßen, T., Lemeshko, M., &#38; Heckl, O. H. (2026). The R-index: A universal metric for evaluating OAM content and mode purity in optical fields. <i>Journal of Physics: Photonics</i>. IOP Publishing. <a href=\"https://doi.org/10.1088/2515-7647/ae3506\">https://doi.org/10.1088/2515-7647/ae3506</a>","mla":"Bahl, Monika, et al. “The R-Index: A Universal Metric for Evaluating OAM Content and Mode Purity in Optical Fields.” <i>Journal of Physics: Photonics</i>, vol. 8, no. 1, 015071, IOP Publishing, 2026, doi:<a href=\"https://doi.org/10.1088/2515-7647/ae3506\">10.1088/2515-7647/ae3506</a>."},"OA_place":"publisher","department":[{"_id":"MiLe"}],"publication":"Journal of Physics: Photonics","date_created":"2026-03-22T23:04:32Z","external_id":{"arxiv":["2508.12973"]},"year":"2026","doi":"10.1088/2515-7647/ae3506","article_number":"015071","status":"public","author":[{"last_name":"Bahl","full_name":"Bahl, Monika","first_name":"Monika"},{"first_name":"Georgios","full_name":"Koutentakis, Georgios","id":"d7b23d3a-9e21-11ec-b482-f76739596b95","last_name":"Koutentakis"},{"id":"2E65BB0E-F248-11E8-B48F-1D18A9856A87","last_name":"Maslov","orcid":"0000-0003-4074-2570","first_name":"Mikhail","full_name":"Maslov, Mikhail"},{"first_name":"Tom","full_name":"Jungnickel, Tom","last_name":"Jungnickel"},{"last_name":"Gaßen","first_name":"Timo","full_name":"Gaßen, Timo"},{"id":"37CB05FA-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0002-6990-7802","last_name":"Lemeshko","first_name":"Mikhail","full_name":"Lemeshko, Mikhail"},{"full_name":"Heckl, Oliver H.","first_name":"Oliver H.","last_name":"Heckl"}],"title":"The R-index: A universal metric for evaluating OAM content and mode purity in optical fields","article_type":"original","publisher":"IOP Publishing","issue":"1","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","intvolume":"         8","month":"03","corr_author":"1","has_accepted_license":"1","day":"10","file_date_updated":"2026-03-23T13:24:01Z","quality_controlled":"1","_id":"21470","acknowledgement":"This research was funded in whole or in part by the Austrian Science Fund (FWF) [10.55776/F1004]. For open access purposes, the author has applied a CC BY public copyright license to any author accepted manuscript version arising from this submission.","OA_type":"hybrid","oa":1,"type":"journal_article","tmp":{"image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"arxiv":1,"oa_version":"Published Version","volume":8,"abstract":[{"text":"Despite its pivotal role in optical manipulation, high capacity communications, and quantum information, a general measure of orbital angular momentum (OAM) in structured light remains elusive. In optical fields, where multiple vortices coexist, the local nature of vortex OAM and the absence of a common rotation axis make the total OAM of the field difficult to quantify. Here, we introduce the R index—a metric that captures the intrinsic OAM content of any structured optical field, from pure Laguerre–Gaussian modes to arbitrary multi vortex superpositions. Not only does this metric quantify the total OAM, it also assesses field purity, providing insight into the fidelity and robustness of the OAM generation. By unifying OAM characterization into a single figure of merit, the R index enables direct comparison across diverse beam profiles and facilitates the identification of optimal configurations for both foundational studies and applied technologies.","lang":"eng"}],"ddc":["530"],"language":[{"iso":"eng"}],"article_processing_charge":"Yes (in subscription journal)","date_updated":"2026-03-23T13:26:26Z","publication_status":"published"}