PhD Defence by Taavi Repän

Title: Dark-field hyperlens: High-contrast subwavelength imaging in optics and acoustics 



Principal supervisor:  Andrei Lavrinenko
Co-supervisor: Morten Willatzen

Evaluation Board
Assoc. Prof. Samel Arslanagic, DTU Elektro
Prof. Dr. Kurt Busch, (Humboldt-Universitaet zu Berlin
Assoc. Prof. Valentyn S. Volkov, University of Southern Denmark

Master of the Ceremony
Assoc. Prof. Niels Gregersen, DTU Fotonik


Aim of the thesis is to explore possibilites for superresolution imaging of weakly scattering objects in bioimaging applications, for example. The thesis contains results of theoretical analysis and numerical simulations. The first half of the thesis gives a comprehensive overview of hyperbolic metamaterials (HMMs): how to describe wave propagation in such structures, how the metamaterial parameters affect wave propagation and behavior, and how to design HMMs using metal-dielectric multilayers. I also explore how such properties come into play when designing hyperlenses for superresolution imaging. The second part of the thesis covers results of the PhD project. I start by presenting the dark-field hyperlens, using the theory developed in the first part of the thesis to discuss design challenges of the dark-field design. The design is based on a metal-dielectric multilayer with realistic material parameters, although as I will discuss the dark-field operation creates several new challenges. Thesis continues with more theoretical work, covering magnetic dark-field hyperlenses. Here I show that by also incorporating negative permeability HMMs we can avoid some of the challenges, that seriously hampered performance of the earlier design. Finally, I move from hyperbolic metamaterials to anisotropic interfaces, which support hyperbolic surface waves. This allows applying the magnetic hyperlens design in a more realistic setting, as surface waves can be engineered to offers similar propagation properties as magnetic metamaterials, without actually requiring magnetic material properties.


tir 26 feb 19
13:30 - 16:30


DTU Fotonik



Lyngby Campus

Building 341, auditorium 22