Transmission and reflection type holograms may be formed utilizing a novel
polymer-dispersed liquid crystal (PDLC) material and its unique switching
characteristics to form optical elements. Applications for these
switchable holograms include communications switches and switchable
transmission, and reflection red, green, and blue lenses. The PDLC
material offers all of the features of holographic photopolymers with the
added advantage that the hologram can be switched on and off with the
application of an electric field. The material is a mixture of a
polymerizable monomer and liquid crystal, along with other ingredients,
including a photoinitiator dye. Upon irradiation, the liquid crystal
separates as a distinct phase of nanometer-size droplets aligned in
periodic channels forming the hologram. The material is called a
holographic polymer-dispersed liquid crystal (H-PDLC).