Pulsed laser annealing for metallic nanorods embedded in alumina

Metallic nanorod metamaterials, arrays of vertically aligned nanorods embedded in an alumina matrix (diameter ∼80 nm, length 100-250 nm, period ∼113 nm), have recently emerged as a flexible platform for applications in photonics, opto-electronics and sensing. The optical constants for these nanostructured materials are directly associated with their crystallinity. Controlling the crystallinity of these metamaterials in a fast manner has presented a new challenge. Here we show a laser annealing with a pulsed Nd:YAG laser (λ = 532 nm, FWHM 15 ns) to rapidly change the crystallinity of the metallic nanorods. The small column X-Ray diffraction characterization shows that not only the crystallinity of the metallic nanorods is changed, but also that evaporation of the metal occurs with laser annealing.