Light Manipulation in Multilayer Metamaterials

Research output: Book/ReportDoctoral thesisCollection of Articles

Abstract

Light manipulation has become much more sophisticated with the development of artificial metamaterials. Here, I have studied multilayer thin film-based hyperbolic metamaterials (HMM) in both planar and cylindrical formations. First, the planar HMMs are used as epsilon-near-zero (ENZ) substrates to control the spectral position of plasmonic resonance. The resonance shift is reduced three times on top of HMM compared to a glass substrate. Next, the thin films are rolled to form three-dimensional (3D) rolled-up tubes (RUT) using a strained induced self-rolling mechanism. The RUTs offer flexibility to use a broad range of materials for rolling by using photoresist and germanium as a sacrificial layer. The RUTs are fabricated with different diameters ranging from ∼1 µm to 10 µm by simply changing the thicknesses of dielectric and metal layers. The walls of the RUTs offer tunable material dispersion and can be used as 3D ENZ metamaterials. While, the core of these RUTs can be used as waveguides, which can support the ENZ mode. The modeling manifests that the material dispersion is a function of the thicknesses of the layers and the number of turns and ENZ mode is very sensitive to the diameter of the RUT. Finally, the upper side of the RUT is patterned to form 3D fishnet metamaterials, which exhibit a negative index of refraction in the near-infrared region with low loss and a better figure of merit. The patterning is further upgraded to form nanohole-based metasurfaces that can control the wavefront of light. The curved metasurfaces out-perform the conventional planar metasurfaces. The large diameter of RUTs provides enough area to pattern a good number of unit cells, that can be optically characterized. The results of this thesis show that the planar HMMs can be used to effectively reduce the fabrication error for advanced metasurfaces and plasmonic applications. The cylindrical HMMs can serve as a unique platform for 3D metamaterials suitable for sensing applications, trapping biological cells, neurons, and optical trapping of particles.
Original languageEnglish
Place of PublicationTampere
ISBN (Electronic)978-952-03-2451-3
Publication statusPublished - 2022
Publication typeG5 Doctoral dissertation (articles)

Publication series

NameTampere University Dissertations - Tampereen yliopiston väitöskirjat
Volume621
ISSN (Print)2489-9860
ISSN (Electronic)2490-0028

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