Electrically Controllable Omnidirectional Laser Emission from a Helical-Polymer Network Composite Film

A liquid-crystal/polymer composite is used to produce a photonic bandgap system. Films of the composite show a large field-induced reversible color shift of the reflection band of over 150 nm. Intensity-controllable laser emission at relatively low lasing thresholds is generated from composite films doped with dye. Moreover, the laser exhibits omnidirectional emission propagation on application of an electric field.