170279 20260410165451.0 doi 10.1364/OE.586633 sideral 148834 ART-2026-148834 eng Lasarte, Jorge Holographic recording on a curved substrate: investigation of a method to increase the numerical aperture in holographic optical lenses 2026 This study investigates methods to enhance the numerical aperture (NA) of holographic optical lenses (HOLs) through innovative holographic recording techniques. The research explores the limits of conventional holographic recording of high NA lenses and presents a novel curved-recording technique with the potential to go beyond these limits. The objective is to obtain high NA HOLs suitable for use with LED sources and other highly-diverging input beams. The work first outlines how the maximum numerical aperture lens achievable through holographic recording is limited by the recording geometry. Next, the effect of curving the substrate during holographic recording, and later returning it to a planar shape for use, is explored in order to demonstrate that this could provide a means of fabricating a higher numerical aperture lens. HOLs are then recorded experimentally, firstly using the standard approach for high NA; the overlap of two beams at a plane photosensitive film with as large a beam aperture as possible, and the focal point as close to the (planar) photopolymer as the geometry will allow. Then, a similar arrangement is used, but with curved photopolymer substrates. Diffraction angles and efficiencies of the resulting holographic lenses are compared with the theoretically predicted Bragg diffraction. HOLs with a 20 mm aperture and focal lengths as short as 12 mm are demonstrated. Access copy available to the general public Unrestricted info:eu-repo/grantAgreement/ES/DGA/E44-23R info:eu-repo/semantics/openAccess by https://creativecommons.org/licenses/by/4.0/deed.es info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Murphy, Kevin Naydenova, Izabela Atencia, Jesús Universidad de Zaragoza (orcid)0000-0001-9804-990X Collados, Ma Victoria Universidad de Zaragoza (orcid)0000-0002-3299-253X Martin, Suzanne 2002 385 Universidad de Zaragoza Dpto. Física Aplicada Área Física Aplicada 2002 647 Universidad de Zaragoza Dpto. Física Aplicada Área Óptica 34, 6 (2026), 10234 [18 pp.] Opt. express OPTICS EXPRESS 1094-4087 5210137 http://zaguan.unizar.es/record/170279/files/texto_completo.pdf Versión publicada 2418818 http://zaguan.unizar.es/record/170279/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:170279 articulos driver 2026-04-10-13:45:44 ARTICLE