doi:10.1364/OE.21.021057engAtencia, J.Collados, M.V.Quintanilla, M.Marín Sáez, J.Sola, I.J.Holographic optical element to generate achromatic vorticesART-2013-82985A compound holographic optical element to generate achromatic vortices with high efficiency, based on the combination of two volume phase holograms, is designed and constructed. This element is compact and easy to align. It has high damage threshold, so it can be used with ultraintense laser pulses.2013http://zaguan.unizar.es/record/5849310.1364/OE.21.021057http://zaguan.unizar.es/record/58493oai:zaguan.unizar.es:58493info:eu-repo/grantAgreement/ES/MINECO/FIS2012-35433OPTICS EXPRESS 21, 18 (2013), 21057-21062byhttp://creativecommons.org/licenses/by/3.0/es/info:eu-repo/semantics/openAccess