Three aluminum (Al)/silicon dioxide (SiO 2 )/aluminum (Al) nanosandwich films (SWFs) of various heights were fabricated using glancing angle deposition. An SWF comprises a 45-nm thick SiO 2 layer sandwiched between two Al nanopillars. The thicknesses of both top and bottom nanopillars were varied from 187.5 to 217.5 nm. The equivalent constitutive and related parameters of each SWF were obtained from the reflection coefficients and transmission coefficients that were measured using a walk-off interferometer. Both the equivalent permittivity and the equivalent permeability of each SWF turned out to be negative real. Exactly how the height of the Al nanopillars of the double negative SWF affects its low reflectance through destructive interference is also examined using the wave tracing method. Moreover, the localized reversed magnetic field in the SiO 2 layer of each SWF was simulated by finite-difference time-domain method to qualitatively interpret the negative real permeability.
In this work, three different aluminum (Al) / silicon-dioxide (SiO2) / aluminum (Al) nanosandwich films (SWFs) with different sizes are deposited using glancing angle deposition (GLAD) with continuous azimuthal rotation. The SWF comprises an SiO2 layer that is sandwiched between Al nanopillars. The thickness of SiO2 is fixed at 45nm. The thicknesses d of the top and bottom Al nanopillar is varied from 188nm to 233nm. The equivalent electromagnetic parameters of each film are derived from the reflection coefficients and transmission coefficients that are measured by walk-off and polarization interferometers. The equivalent optical parameters revealed that it has a negative real equivalent permittivity and a negative real equivalent permeability. The effect of size of the Al / SiO2 / Al SWFs on their optical properties is also examined. As the thickness d increases from 188nm to 233nm, the equivalent refractive index is negative and its average magnitude decreases from -1.703 to -1.247. Similarly, the real part of the equivalent permittivity varies from -1.193 to -0.824 as the thickness increased. The SWFs are simulated to analyze the magnetic field in the SiO2 layer by finite-difference time-domain (FDTD) method. The result of the simulation shows that the negative permeability arises from the reversal of the magnetic resonance within the SiO2 layer. The reversed magnetic field becomes weaker as the thickness d increases.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.