Advanced Materials · 2001 · 160 citations · 0 references
Natural SciencesMaterials SciencePhysicsOptical MaterialsOpticsPhotonicsLaser OpticsLaser PhysicsLuminescent MaterialsOptical Properties Of MaterialsOptical SourcesPhotonic CrystalsAmplified Spontaneous EmissionConjugated PolymersExcitationLasersPhoton StatisticsResonant CavitiesScatteringSpontaneous Emission
Random lasers in π‑conjugated polymer films and opal‑infiltrated solutions are reviewed. Random lasing is a generic, coherent phenomenon that occurs in disordered π‑conjugated polymer films and opal‑infiltrated solutions at high excitation, producing multiple laser modes, enabling multi‑color emission through dye mixing, and spanning scattering regimes from pre‑localization to weak scattering.
The properties of random lasers in π-conjugated polymer films and solutions infiltrated into opal photonic crystals are reviewed. We show that random lasing is a generic phenomenon that occurs in disordered gain media at an excitation intensity regime higher than that giving rise to amplified spontaneous emission. The emission radiation is coherent as demonstrated by photon statistics methods, and its spectrum contains many laser modes from which a typical cavity length can be obtained using Fourier transform spectroscopy. Since the random cavities are independent from each other, we show that laser emission in several colors is possible when mixing different dyes in the same random cavities. In addition, it is demonstrated that random lasing is formed in many disordered media with various scattering properties ranging from a regime of light prelocalization to that of weak scattering.