Multilayer metal-oxide-metal nanopatterns via nanoimprint and strip-off for multispectral resonance

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>A fabrication technology for multispectral plasmonic resonators is presented on a basis of metal-insulator-metal (MIM) nanopattern arrays. Resonators comprised of MIM nanopatterns were fabricated using nanoimprint-based transfer and strip-off following MIM depositions. Two different kinds of configuration (web and hole) were developed for three and five layers of MIMs. The corresponding measured transmittance and reflectance spectroscopies were compared to their counterpart finite difference time domain (FDTD) simulation results. The results implied various plasmonic resonance couplings occurred at different locations around the metal structures, dependent on the layer and array configuration. By tuning the model geometry and simulation conditions, agreement between the experimental results and simulation was achieved. This work is believed to provide a viable fabrication method for multispectral resonance filters or sensors.</P> <P><B>Graphical abstract</B></P> <P>(a) First, we developed a fabrication strategy for discrete multilayer nanopattern arrays comprised of alternate stacks of metal and oxide, the process of which is based on nanoimprint-coupled strip-off. The figure below shows five layers of alternating Ag and oxide in the web-trench (left) and hole arrays (right) after selective strip-off of the multilayers deposited only on the raised surface of the nanoimprinted patterns.</P> <P>(b) Second, we demonstrated explicit multispectral resonance peaks by both experimental measurements and an FDTD simulation, which are correlated with the number of stacks in metal-oxide-metal layers. Assisted by reflectance spectroscopy, the extinction peaks were estimated to result from MIM absorption and its associated resonance rather than reflective scattering. The figures below show both transmittance and reflectance of the experimental (Left) and simulation (Middle) results, in addition to the E-field distribution at the resonant wavelengths (Right) of the sample with 3MIMs deposited in hole arrays. Resonant peak wavelengths were formed at 643 and 810nm (experimental measurements), and at 675 and 870nm (FDTD simulation). Localized E-fields at each resonant wavelength were created strongly around the Ag layer, and result from the in-phase and out of phase charge oscillations inside the two Ag layers.</P> <P>[DISPLAY OMISSION]</P>