Holographic polymer-dispersed liquid crystal, a new class of composite electro-optic materials, has rapidly matured as a technology for electronically switchable Bragg gratings. Recent progress in H-PDLC materials science has improved basic understanding of the mechanisms of diffusion, nanodroplet formation, and the morphology underlying switchable holograms, leading to practical improvements in key parameters such as the switching ratio, speed and operating voltage and an ability to optimize formulations for varied device functions such a switchable lenses and switchable waveguide Bragg gratings. Combining lens, filter or holographic optical functions with switchability leads to reduced parts count and simplified designs for projection displays and compact wearable microdisplays. H-PDLC technology is now approaching the performance and stability requirements that will enable photonic applications such as low cost WDM switches for optical networks.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.