Modeling of ZnO nanorods for evanescent field optical sensors

Abstract

The optical wave guiding properties of ZnO nanorods are simulated and studied in detail using a block‐iterative frequency‐domain method and the results of a finite difference method as reference data. The simulations are performed for different wavelengths in the infrared spectral region that are related to specific gas absorption lines. Here both single ZnO nanorods and nanorod arrays with varying period lengths are investigated. The evanescent field distributions and penetration depths into the surrounding media are analyzed and compared as a function of wavelength and rod diameter. Our results give a general overview on the size range where ZnO nanorods may be used for evanescent field interaction based sensors for the detection of gas molecules like CO, CO2 or O2. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Zinc Oxide Nanomaterials for Biomedical Fluorescence Detection

“…In theoretical simulations based on MIT Photonic Bands (MPB) program and Finite Difference Method (FDM), the penetration depth of the evanescent field around a hexagonal ZnO NR with a diameter of 500 nm was predicted as approximately 125 nm when excitation of 761 nm was used. 91 Figure 7 summarizes these simulation results on the evanescent field of ZnO NR. The outcomes corroborate with the observation of a relatively large decay length of fluorescence enhancement (much longer than 100 nm) in ZnO NR biodetection systems.…”

“…Reprinted with permission from Ref. #91, S. Börner, C. E. Rüter, T. Voss, D. Kip, and W. Schade, Phys. Stat.…”

Fundamental Properties of One-Dimensional Zinc Oxide Nanomaterials and Implementations in Various Detection Modes of Enhanced Biosensing

“…1D subwavelength waveguides not only carry a larger fraction of their modal power outside the core compared to conventional optical fibers, but also enhance the evanescent wave field and its penetration depth. The penetration depth of an evanescent field around a hexagonal ZnO NR, predicted by theoretical simulations based on the MIT Photonic-Bands program and finite-difference method, is approximately 125 nm for a NR of 500 nm in diameter for 761-nm light (77). Figure 4 c displays 2D finite-difference time-domain (FDTD) calculation results of the electric field ( E ) of a light pulse emitted from a NR by varying the NR diameter ( d ) from 300 nm to 1 µm while considering E within the NR cavity as well as outside as a surface evanescent wave.…”

“…( e ) Penetration depth ( d p ) obtained by the MIT Photonic-Bands (MPB) program and the finite-difference method (FDM) as a function of diameter for λ = 761 nm. Panels c, d , and e adapted from Reference 77 with permission. Copyright 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.…”

Scattering attributes of one-dimensional semiconducting oxide nanomaterials individually probed for varying light-matter interaction angles

“…Light can produce various optical and optoelectronic responses from the materials and, therefore, light-matter interactions can be engineered to produce desirable optical properties such as spontaneous and stimulated emission, 1,25-29 waveguiding, 1-3 and evanescence field enhancement. 4,[30][31][32] Such examples can be seen in the research efforts previously reported for the development of SO nanomaterials for applications in nanoscale lasers, 25,26,29 subwavelength waveguides, 1-3,33,34 and biodetection platforms. 17,18,20,23,24,33,35 Specifically, nanomaterials of zinc oxide (ZnO), tin oxide (SnO 2 ), indium tin oxide (ITO), and zinc tin oxide (ZTO) have been widely utilized as signal transduction elements in optical detection devices.…”