title: Facile synthesis of optical microcavities by a rationally designed anodization approach: tailoring photonic signals by nanopore structure.
abstract: Structural engineering of porous anodic aluminum oxide (AAO) nanostructures by anodization has been extensively studied in the past two decades. However, the transition of this technique into the fabrication of AAO-based one-dimensional photonic crystal is still challenging. Herein, we report for the first time on the fabrication of AAO optical microcavities by a rationally designed anodization approach. In our study, two feasible methods are used to fabricate microcavities with tunable resonance peak across the visible and near-infrared spectra. Distributed Bragg reflector (DBR) nanostructures are first fabricated by pulse anodization approach, in which the anodization voltage was periodically manipulated to achieve pseudosinusoidal modulation of the effective refractive index gradient along the depth of the AAO nanostructures. Microcavities were created by creating a nanoporous layer of constant porosity between two AAO-DBR nanostructures, and by introducing a shift of the phase of the porosity gradient along the depth of AAO. The position of the resonance peak in these microcavities can be linearly tuned by means of the duration of the high voltage anodization. These optical nanostructures are sensitive to alterations of the effective media inside the nanopores. The AAO microcavity shows a central wavelength shift of 2.58 ± 0.37 nm when exposed to water vapor. Our research highlights the feasibility of anodization technique to fabricate AAO-based photonic nanostructures for advanced sensing applications.
authors.affiliation: †School of Chemical Engineering, The University of Adelaide, Adelaide, SA 5005, Australia.|‡Discipline of Surgery, Basil Hetzel Institute, The University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Ye
authors.initials: Y
authors.lastname: Wang
authors.affiliation: †School of Chemical Engineering, The University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Chen
authors.affiliation: †School of Chemical Engineering, The University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Tushar
authors.initials: T
authors.lastname: Kumeria
authors.affiliation: †School of Chemical Engineering, The University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Fuyuan
authors.initials: F
authors.lastname: Ding
authors.affiliation: ‡Discipline of Surgery, Basil Hetzel Institute, The University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Andreas
authors.initials: A
authors.lastname: Evdokiou
authors.affiliation: †School of Chemical Engineering, The University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Dusan
authors.initials: D
authors.lastname: Losic
authors.affiliation: †School of Chemical Engineering, The University of Adelaide, Adelaide, SA 5005, Australia.
authors.forename: Abel
authors.initials: A
authors.lastname: Santos
keywords: anodic aluminum oxide; chemical sensing; distributed Bragg reflectors; electrochemical anodization; microcavities; nanopores; photonic crystal