Two dyes for holographic recording material: panchromatic ion pair from Rose Bengal and Methylene Blue

摘要

An ion pair (RBMB) isolated froM Rose Bengal and Methylene Blue has been used as the photoinitiator in formulations of photopolymers tested as holographic recording materials in the form of dry films. Under irradiation with light of wavelength 633 or 514 nm, diffraction efficiencies of 65 and 35%, and sensitivities of 30 and 100 mJ cm~(-2) have been respectively reached, with a spatial resolution of ca. 1000 lines mm~(-1). These holographic responses are better than those reached under comparative conditions using a 1:1 physical mixture of the individual dyes. The influence of the light intensity on the photoinitiation of the polymerization process yielding the hologram has also been studied.