A method of replicating a plurality of optical elements, the method including the steps of: - providing a substrate with a first and a second large side and a plurality of pre-defined replication sites defined by through holes or pairs of blind holes at corresponding locations on both large sides of the substrate; - adding, by replication, a replicated structure to the substrate, the replicated structure adhering to the substrate and comprising, at said replication sites, replication material in said through hole or in said two blind holes, respectively and a first replicated surface and a second replicated surface, the first and second replicated surfaces facing towards opposite sides, wherein the step of adding, by replication, a replicated structure to the substrate comprises moving a replication tool (31, 32) and the substrate towards each other with replication material (51, 52) on the replication tool and/or in the through holes or blind holes, the replication tool (31, 32) comprising a replication structure being the negative of a surface structure of the optical elements to be replicated; wherein the substrate is chosen to comprise through holes defining the replication sites, and wherein the step of adding, by replication, a replicated structure comprises the sub-steps of: - moving a first replication tool comprising first replication sections and the first large side towards each other, until the first replication tool and the substrate are in a pre-defined positional relationship, and with replication material in said holes and in contact with the first replication section; - hardening the replication material to provide hardened replication material adhering to the substrate; - moving a second replication tool comprising second replication sections and the second large side towards each other, until the second replication tool and the substrate are in a pre-defined positional relationship, and with further replication material in contact with the second replication sections and with the hardened replication material; and - hardening the further replication material. - providing a substrate with a first and a second large side and a plurality of pre-defined replication sites defined by through holes or pairs of blind holes at corresponding locations on both large sides of the substrate; - adding, by replication, a replicated structure to the substrate, the replicated structure adhering to the substrate and comprising, at said replication sites, replication material in said through hole or in said two blind holes, respectively and a first replicated surface and a second replicated surface, the first and second replicated surfaces facing towards opposite sides, wherein the step of adding, by replication, a replicated structure to the substrate comprises moving a replication tool (31, 32) and the substrate towards each other with replication material (51, 52) on the replication tool and/or in the through holes or blind holes, the replication tool (31, 32) comprising a replication structure being the negative of a surface structure of the optical elements to be replicated; - moving a first replication tool comprising first replication sections and the first large side towards each other, until the first replication tool and the substrate are in a pre-defined positional relationship, and with replication material in said holes and in contact with the first replication section; - hardening the replication material to provide hardened replication material adhering to the substrate; - moving a second replication tool comprising second replication sections and the second large side towards each other, until the second replication tool and the substrate are in a pre-defined positional relationship, and with further replication material in contact with the second replication sections and with the hardened replication material; and - hardening the further replication material.