Mesostructured waveguides exhibit mirrorless lasing

Working with colleagues at Harvard University (Cambridge, MA), researchers at the University of California (Santa Barbara, CA) have fabricated mesostructured silica-waveguide arrays in which waveguiding was enabled using a low-refractive-index mesoporous-silica thin-film support. When each mesostructure was doped with a laser dye, it exhibited amplified spontaneous emission with a low pumping threshold of 10 kW/cm². The researchers attributed this mirrorless lasing to the mesostructure's ability to prevent aggregation of the dye molecules, even at a relatively high loading within the organized high-surface-area mesochannels of the waveguides. They anticipate that many other dye molecules, rare-earth complexes, or nanocrystals can be incorporated into mesostructures to obtain different optical properties and functions via the tuning of the host architecture, the orientation and alignment of the guest species, and control of the host-guest interactions. In addition, waveguide building is done using a low-cost, one-step self-assembly process that combines acidic sol-gel block copolymer templating chemistry and micromolding, micromolding in capillaries, and microtransfer molding--soft lithographic techniques that have already proved themselves in the rapid, low-cost fabrication of liquid-core, polymeric, and inorganic waveguides. Contact Galen Stucky at [email protected].