Engineering of Solid-State Random Lasing in Nanoporous Anodic Alumina Photonic Crystals

Abstract

Random lasing provides new opportunities to engineer cost-competitive, highly controllable, and integrable light sources for a broad range of photonic technologies such as sensing, hyperspectral imaging, high-resolution spectroscopic analysis, and photonic circuits. In this study, we engineer the self-organized structure of nanoporous anodic alumina (NAA) through the electrochemical oxidation of aluminum to generate a palette of model nanoporous platforms with tailored, hexagonally distributed, straight cylindrical nanopores. The inner surface of these platforms is functionalized with a model organic fluorophore via micellar solubilization of a surfactant. The resultant organic–inorganic composite structures provide model platforms to develop optically pumped solid-state random lasers with well-resolved, intense lasing bands. The effect of NAA’s geometric features on the random lasing characteristics of these model platforms is elucidated by precisely engineering its nanopore diameter, nanopore length, interpore distance, and ordering. Structural engineering of NAA makes it possible to tune and maximize random-lasing emissions, resulting in strong, polarized lasing at ∼628 nm characterized by a remarkably high-quality-gain product of ∼1433, a polarization quality of ∼0.9, and a lasing threshold of ∼0.87 mJ pulse–1.

Review of Catalysts, Substrates, and Fabrication Methods in Catalytic Hydrogen Combustion with Further Challenges and Applications

“…Schematic and characterization of NAA using sulfuric, oxalic, and phosphoric acids in the anodization process: (a) geometric features of NAA fabricated by sulfuric acid (NAA Su ), (b) top and cross-sectional view scanning electron microscopy (SEM) images of NAA Su , (c) geometric features of NAA fabricated by oxalic acid (NAA Ox ), (d) top and cross-sectional view SEM images of NAA Ox , (e) geometric features of NAA fabricated by phosphoric acid (NAA Ph ), and (f) top and cross-sectional view SEM images of NAA Ph . This figure was reproduced with permission from ref . Copyright 2022 American Chemical Society.…”

Detection of Volatile Organic Compounds through Spectroscopic Signatures in Nanoporous Fabry–Pérot Optical Microcavities

“…Details of the anodization setup and conditions are reported elsewhere. 28 The anodization process consisted of two stages: (i) an initial constant current density (J) stage and (ii) a pulsed current density-controlled stage. The first stage was controlled at a constant current density of J = 1.120 mA•cm −2 for 10 min.…”

Engineering of Solid-State Nanoporous Laser through Dendrimer-Encapsulated Fluorophores

“…Of all these, optically inert nanoporous structures functionalized with light-emitting materials provide ideal platforms to create random lasing systems, where stimulated light emission can be precisely tuned by engineering the features of the scattering centers (pores) by various fabrication methods such as wet and dry chemical etching, imprinting, and template synthesis . Of all these potential structures, nanoporous anodic alumina (NAA) is an ideal solid-state platform material for developing lasing systems harnessing distinct optical phenomena (e.g., slow photons, random lasing). − NAA produced by anodization (electrochemical oxidation) of aluminum is a thin film of anodic aluminum oxide (alumina, Al 2 O 3 ) that features straight cylindrical nanopores along its thickness, from top to bottom and is homogeneously distributed across its surface. , NAA’s nanopores act as scattering centers, the geometric features of which can be tuned through anodization. Furthermore, NAA is chemically stable and mechanically robust, and its inner porous structure can be functionalized with a variety of light-emitting materials, providing a broad range of opportunities to engineer new forms of gain media.…”