School of Chemical Engineering, The University of Adelaide, Engineering North Building, 5005 Adelaide, Australia.
Nanoscale. 2016 Aug 4;8(31):14846-57. doi: 10.1039/c6nr03490j.
Herein, we present a rationally designed advanced nanofabrication approach aiming at producing a new type of optical bandpass filters based on nanoporous anodic alumina photonic crystals. The photonic stop band of nanoporous anodic alumina (NAA) is engineered in depth by means of a pseudo-stepwise pulse anodisation (PSPA) approach consisting of pseudo-stepwise asymmetric current density pulses. This nanofabrication method makes it possible to tune the transmission bands of NAA at specific wavelengths and bandwidths, which can be broadly modified across the UV-visible-NIR spectrum through the anodisation period (i.e. time between consecutive pulses). First, we establish the effect of the anodisation period as a means of tuning the position and width of the transmission bands of NAA across the UV-visible-NIR spectrum. To this end, a set of nanoporous anodic alumina bandpass filters (NAA-BPFs) are produced with different anodisation periods, ranging from 500 to 1200 s, and their optical properties (i.e. characteristic transmission bands and interferometric colours) are systematically assessed. Then, we demonstrate that the rational combination of stacked NAA-BPFs consisting of layers of NAA produced with different PSPA periods can be readily used to create a set of unique and highly selective optical bandpass filters with characteristic transmission bands, the position, width and number of which can be precisely engineered by this rational anodisation approach. Finally, as a proof-of-concept, we demonstrate that the superposition of stacked NAA-BPFs produced with slight modifications of the anodisation period enables the fabrication of NAA-BPFs with unprecedented broad transmission bands across the UV-visible-NIR spectrum. The results obtained from our study constitute the first comprehensive rationale towards advanced NAA-BPFs with fully controllable photonic properties. These photonic crystal structures could become a promising alternative to traditional optical bandpass filters based on glass and plastic.
在此，我们提出了一种合理设计的先进纳米制造方法，旨在基于纳米多孔阳极氧化铝光子晶体生产新型光学带通滤波器。通过采用由伪阶跃非对称电流密度脉冲组成的伪阶跃脉冲阳极氧化 (PSPA) 方法，对纳米多孔阳极氧化铝 (NAA) 的光子带隙进行了深度工程设计。这种纳米制造方法使得可以在特定波长和带宽下调节 NAA 的传输带，通过阳极氧化周期（即连续脉冲之间的时间）可以在整个 UV-可见-NIR 光谱中广泛修改。首先，我们确定了阳极氧化周期作为调节 NAA 在 UV-可见-NIR 光谱中传输带位置和宽度的方法的效果。为此，制作了一组具有不同阳极氧化周期的纳米多孔阳极氧化铝带通滤波器 (NAA-BPFs)，范围从 500 到 1200 s，并且系统地评估了它们的光学性质（即特征传输带和干涉颜色）。然后，我们证明了由具有不同 PSPA 周期的 NAA 层组成的堆叠 NAA-BPF 的合理组合可以很容易地用于创建一组具有独特且高度选择性的光学带通滤波器，其特征传输带的位置、宽度和数量可以通过这种合理的阳极氧化方法进行精确设计。最后，作为概念验证，我们证明了通过稍微修改阳极氧化周期来堆叠 NAA-BPF 的叠加可以制造具有前所未有的宽 UV-可见-NIR 光谱传输带的 NAA-BPF。我们的研究结果构成了具有完全可控制的光子特性的先进 NAA-BPF 的第一个综合原理。这些光子晶体结构可能成为基于玻璃和塑料的传统光学带通滤波器的有前途的替代品。
