Electrically controlled white laser emission through liquid crystal/polymer multiphases

White lasers are becoming increasingly relevant in various fields since they exhibit unprecedented properties in terms of beam brightness and intensity modulation. Here we introduce a white laser based on a polymer matrix encompassing liquid crystals and multiple organic chromophores in a multifunctional phase-separation system. The separation of the hydrophilic matrix and the hydrophobic liquid crystals leads to the formation of a complex optically active layer, featuring lasing emission tuneable from blue to red. White laser emission is found with an optical excitation threshold of approximately 12 mJ/cm(2). Importantly, an external electric field can be used to control the device emission intensity. White lasers with low-voltage (<= 10 V) controllable emission might pave the way for a new generation of broadband light sources for analytical, computational, and communication applications. Organic lasers: Polymer suspensions see the white A laser that can emit white light has been fabricated by mixing liquid crystal particles and polymers into an emulsion. Devices that use organic compounds to produce white light are normally fabricated by combining differently coloured lasers together. Camposeo Andrea from Italy's Istituto Nanoscienze-CNR and colleagues have now achieved similar effects in a more compact set-up by utilizing phase separations between water-repelling and water-attracting molecules. The team incorporated hydrophobic liquid crystal droplets, which emit green or red light, into a hydrophilic alcohol containing blue-emitting compounds. Analysis of the polymer emulsion revealed that it had a layered structure that may enhance both individual colour emissions and the blending into white light. Sandwiching the organic laser between a pair of transparent electrodes enabled the authors to manipulate the white laser intensity with a small voltage.