Tailoring the nanostructure of anodic aluminum oxide cladding on optical fiber

Abstract

We report a comprehensive investigation of fabricating nanostructured anodic aluminum oxide (AAO) cladding on optical fiber. We show that the pore size and interpore distance in the AAO cladding with pore channels vertically aligned to fiber surface can be readily controlled by applied voltage, the type, and concentration of electrolytic acid during anodization of aluminum‐coated optical fiber. The structural characteristics of the AAO cladding were examined by scanning electron microscopy (SEM) and analyzed using ImageJ software. Processing maps correlating AAO growth and anodization parameters were established. Compared to planar AAO growth on aluminum foil, higher growth rate as well as larger pore diameter and interpore distance were observed for AAO cladding formation on optical fiber under identical anodization conditions due to circumferential tensile stress in the AAO growth front at the convex AAO/aluminum interface. This tensile stress also contributed to radial cracking of the AAO cladding upon exceeding some threshold thickness.

Plasmonic Au nanorods stabilized within anodic aluminum oxide pore channels against high-temperature treatment

“…Due to its tailorable porous morphology, anodized aluminum oxide (AAO) has been explored as optical fiber cladding [15][16][17][18][19] and templates for nanomaterials synthesis [20][21][22], solution-phase crystal growth [23][24][25] and plasmonic nanostructure deposition [26,27]. In this work, we report the use of AAO with uniaxially-aligned nanoporous channels as a scaffold to stabilize Au NRs at elevated temperatures.…”