In metal-enhanced fluorescence (MEF), the localized surface plasmon resonances of metallic nanostructures amplify the absorption of excitation light and assist in radiating the consequent fluorescence of nearby molecules to the far-field. This effect is at the base of various technologies that have strong impact on fields such as optics, medical diagnostics, and biotechnology. Among possible emission bands, those in the near-infrared (NIR) are particularly intriguing and widely used in proteomics and genomics due to its noninvasive character for biomolecules, living cells, and tissues, which greatly motivates the development of effective and, eventually, multifunctional NIR-MEF platforms. Here, we demonstrate NIR-MEF substrates based on Au nanocages micropatterned with a tight spatial control. The dependence of the fluorescence enhancement on the distance between the nanocage and the radiating dipoles is investigated experimentally and modeled by taking into account the local electric field enhancement and the modified radiation and absorption rates of the emitting molecules. At a distance around 80 nm, a maximum enhancement up to 2–7 times with respect to the emission from pristine dyes (in the region 660–740 nm) is estimated for films and electrospun nanofibers. Due to their chemical stability, finely tunable plasmon resonances, and large light absorption cross sections, Au nanocages are ideal NIR-MEF agents. When these properties are integrated with the hollow interior and controllable surface porosity, it is feasible to develop a nanoscale system for targeted drug delivery with the diagnostic information encoded in the fluorophore.

Imprinted, distributed feedback lasers are demonstrated on individual, active electrospun polymer nanofibers. In addition to advantages related to miniaturization, optical confinement and grating nanopatterning lead to a significant threshold reduction compared to conventional thin-film lasers. The possibility of imprinting arbitrary photonic crystal geometries on electrospun lasing nanofibers opens new opportunities for realizing optical circuits and chips.

Room temperature nanoimprinting lithography is used to realize a distributed feedback laser by direct dry pressing of the conjugated polymer (poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]). The laser device exhibits emission at 630 nm with a pump threshold of 25 mu J/cm(2) and a polarization contrast of the emitted light as large as 0.91. Therefore, room temperature nanoimprint lithography turns out to be very effective for producing stable patterns on light-emitting polymers for the one-step fabrication of nanopatterned optoelectronic devices. (c) 2006 American Institute of Physics

We report on a monolithic polymeric microcavity laser with all dielectric mirrors realized by low-temperature electron-beam evaporation. The vertical heterostructure was realized by 9.5 TiO x / SiO x pairs evaporated onto an active conjugated polymer, that was previously spincast onto the bottom distributed Bragg reflector ͑DBR͒. The cavity supports single-mode lasing at 509 nm, with a linewidth of 1.8 nm, and a lasing threshold of 84 J/cm 2 . We also report on the emission properties of the polymer we used, investigated by a pump-probe technique. These results show that low-temperature electron-beam evaporation is a powerful and straightforward fabrication technique for molecular-based fully integrable microcavity resonators.