Preparation, characterization, and heat resistance studies of a holographic photopolymer based on SU-8 epoxy resin.
A holographic photopolymer based on SU-8 epoxy resin as the binder and trimethylolpropane ethoxylate triacrylate as the monomer with an iodonium salt photoinitiator was studied. A diffraction efficiency of 93% and a refractive index modulation (Delta n) of 1.3 x 10(-2) were obtained from a 16 microm thick sample with write beam intensities of 50 mW/cm(2) at a wavelength of 514.5 nm, an exposure time of 60 s, and a postbaking at 65 degrees C for 1 h. The material exhibits good heat resistance in the range from 40 degrees C to 160 degrees C and long projected life.