Waveguide lasing in dye-infiltrated nanoporous anodic alumina membranes

What is it about?

In the last few years, intensive studies have been carried out to achieve lasing emission by confining the light in miniaturized cavities and in highly scattering random media. Due to advances in micro and nanofabrication techniques, the field has gained tremendous attention. A nanostructured system that can be attractive in this context is the nanoporous anodic alumina (NAA). To achieve laser-like emission in this system, we utilize the porous volume of NAA and load the amplifying dye into its nanopores. Automatic wetting of the nanostructured surface and evaporation of alcohol ensures a continuous flow of dye and avoids the quenching effects. Laser emission is obtained by pumping the dye-loaded NAA membrane with a ps laser. The refractive index mismatch at the outer and inner facets of the NAA form a planar waveguide which provides the optical confinement for the emitted light. Enhanced emission and bandwidth collapse are observed along the pump light stripe. The large polarization anisotropy confirms the dominance of waveguide effects over any possible random laser effects due to the inherent scattering present in NAA.

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