Improvement of holographic recording material using aerosol sealant

Self-processing photopolymer based materials offer significant practical ad vantages when recording holographic optical elements, HOEs. However, such m aterials, e.g. acrylamide based photopolymer, are seriously effected by amb ient environmental conditions, in particular by fluctuations in humidity. S uch sensitivity can result in a short active material shelf-life prior to r ecording, material variations during the recording and self-processing stag es and HOE deterioration following recording. In this paper we examine the use of an aerosol sealant (varnish) to 'insulate' the photopolymer holograp hic recording material from the environment. Application of the sealant is found to produce some deterioration in the optical quality of the resulting HOEs. However, it is also shown to produce an increased lifetime of the ac tive material (pre-recording), an increase in the diffraction efficiency fr om the resulting diffraction gratings recorded and improved HOE shelf-life.