Pyrromethene-HEMA-based photopolymerizable holographic recording material S. Blaya * , P. Acebal, L. Carretero, A. Fimia Departamento de Ciencia y Tecnolog  ıa de materiales, Universidad Miguel Hern andez, Av. Ferrocarril s/n Apdo. 03202 Elche, Torrevaillo, Elx (Alicante), Spain Received 17 June 2003; received in revised form 23 September 2003; accepted 24 September 2003 Abstract A simple photopolymerizable dry polymeric film based on pyrromethene dye (PM567) which it has been usually used in solid-state dye lasers, has been developed. This new composition is based on only three components: poly-(meth- ylmethacrylate) (PMMA) as a binder, 2-hydroxyethylmethacrylate (HEMA) as a monomer and 1,3,5,7,8-pentamethyl- 2,6-diethylpyrromethene-difluoroborate (PM567) as photoinitiator. Diffraction efficiencies near 60% are obtained with exposures of 1 J/cm 2 in materials of 500 lm of thickness. We have studied the holographic properties of the material when the concentration of monomer and intensity are changed, obtaining good results at low intensities, which it implies that this material can be used in applications based on low power lasers. Ó 2003 Elsevier B.V. All rights reserved. PACS: 42.70.L; 61.41; 42.70.J Keywords: Holography; Photopolymer; Pyrromethene 1. Introduction Much research has already been devoted in dry photopolymer films as holographic recording ma- terials, because of their special properties, such as high diffraction efficiency, low noise, real-time processing and low cost. These materials are an important option for displays, high density data storage, micro-optical elements and other infor- mation processing applications [1–5]. In order to develop new compositions or to optimize previ- ously described systems, many points must be ta- ken into account, such as high diffraction efficiency with low energetic exposures, capability to obtain high spatial-frequency holograms and temporal stability [6–9]. Also, in order to use these materials in holographic data storage, these compositions may accomplish the possibility to have high thicknesses with high signal-to-noise ratio [10]. Pyrromethene dyes have been widely used as solid-state dye lasers due to the high energy con- version, high lifetime and operational photosta- bility [11,12]. These organic dyes have been used in * Corresponding author. Tel.: +34-966658612; fax: +34- 966658497. E-mail address: salva@dite.umh.es (S. Blaya). 0030-4018/$ - see front matter Ó 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.optcom.2003.09.068 Optics Communications 228 (2003) 55–61 www.elsevier.com/locate/optcom