• liquid crystals;
  • photonic crystals;
  • photonics;
  • sol–gel materials;
  • thin films
Thumbnail image of graphical abstract

The picture shows an inorganic glass fi lm with multiple photonic band gaps (MPBGs). The fi lm is fabricated by sol-gel processing of TiO2, SiO2, and mixed SiO2-TiO2 films. In the visible region, the spectral characteristics of MPBGs can be controlled by adjusting fabrication parameters. Using the film with engineered MPBGs, pixelated redgreenblue lasing emissions are achieved in a single sol-gel resonator with three kinds of dye-doped nematic liquid crystals. With easy fabrication via wet-processing, unique optical characteristics, and the advantages of an inorganic glass, the new sol-gel film is a functional substrate with enhanced optical performance for wide-band photonic applications such as refl ective displays, organic lasers, and organic light-emitting diodes.