Efficient and stable holographic gratings stored in an environmentally friendly photopolymer

Holographic gratings stored in low-toxicity photopolymer, Biophotopol, have been analyzed to achieve stable and efficient holograms. A curing process allows the hologram stabilization, but at the same time, it could produce a diffraction efficiency (DE) reduction. Here, a detailed low-cost LED curing protocol is shown to stabilize over time 1205 l/mm transmission holograms, and at the same time, a 33% DE increment (with respect non-curing holograms) have been demonstrated. Finally, to obtain a better understanding of DE change, a theoretical fit of our experimental result, based on Kogelnik’s coupled wave theory was carried out and discussed.Ministerio de Ciencia, Innovación y Universidades, Spain, under projects FIS2017-82919-R (MINECO/AE/FEDER, UE) and FIS2015-66570-P (MINECO/FEDER); Generalitat Valenciana, Spain, under project CDEIGENT/2018/024 and GRE17-06