THz spectroscopy; Metamaterials; Photonic structures; THz near-field measurement; THz metamaterials
Peter Peier, K.A. Nelson, T. Feurer, Coherent phase contrast imaging of THz phonon-polariton tunneling, in Applied Physics B
, 98, 3886-3886.
M. Shalaby, H. Merbold, M. Peccianti, L. Razzari, G. Sharma, T. Ozaki, R. Morandotti, T. Feurer, A. Weber, L. Heydermann, B. Patterson, H. Sigg, Concurrent field enhancement and high transmission of THz radiation in nanoslit arrays, in APL
, 99, 041110-041110.
Birgit Paivanranta, H. Merbold, R. Giannini, L. Buechi, S. Gorelick, C. David, J. Loeffler, T. Feurer, Y. Ekinci, High Aspect Ratio Plasmonic Nanostructures for Sensing Applications, in ACS Nano
, 5(8), 6374-6382.
Peter Peier, Hannes Merbold, V. Pashinin, K.A. Nelson, T. Feurer, Imaging of THz waves in 2D photonic crystal structures embedded in a slab waveguide, in New Journal of Physics
, 12, 013014-013014.
Hannes Merbold, Andreas Bitzer, Thomas Feurer, Near-field investigation of induced transparency in similarly oriented double split-ring resonators, in Opt. Lett.
, 36(10), 1683-1685.
Hannes Merbold, Andreas Bitzer, Thomas Feurer, Second harmonic generation based on strong ﬁeld enhancement in nanostructured THz materials, in Opt. Express
, 19(8), 7262-7270.
H. Merbold, T. Feurer, Slit waveguide based terahertz near-field microscopy: Prospects and limitations, in Journal of Applied Physics
, 107, 033504-033504.
Hannes Merbold, A. Bitzer, F. Enderli, T. Feurer, Spatiotemporal Visualization of THz Near-Fields in Metamaterial Arrays, in Journal of Infrared, Millimeter and Terahertz Waves
Andreas Bitzer, Alex Ortner, Hannes Merbold, Thomas Feurer, Markus Walther, Terahertz near-ﬁeld microscopy of complementary planar metamaterials: Babinet’s principle, in Optics Express
, 19(3), 2537-2542.
With the advent of meta-materials, which are constructed from sub-wavelength resonating structures, unprecedented electromagnetic material properties became accessible. These unusual properties are based on the microscopic electric and magnetic response of the constituting building blocks to an incident electromagnetic wave. As a result, artificially engineered meta-materials make possible a range of fascinating new applications. Since their first demonstration at microwave frequencies progress in miniaturization allowed for fabrication of meta-materials for higher frequencies up to the near-infrared regime. Typically, the fundamental building blocks are made of metallic structures, e.g. split-ring resonators, which are specifically designed to respond resonantly to the electric and the magnetic fields of an incident electromagnetic wave. Close to resonance the induced fields can exceed the incident fields by orders of magnitude and generate a counteracting material response which can lead, for example, to a negative refractive index. So far, photonic meta-materials are mostly characterized by far-field measurements and experimental investigations of the microscopic electric and in particular the magnetic near-fields in meta-materials remain highly challenging. Therefore, it is no surprise that current studies rely mostly on numerical simulations.In the past we have developed experimental means which are suitable to measure electric near-field distributions in the THz spectral range and here we plan to extend those methods to highly sophisticated next generation detection apparatuses. In addition, we have mastered different fabrication processes for highly flexible fabrication of such sub-wavelength structures. We want to apply these new techniques to a number of related problems. The overall theme of the proposal is to understand the linear and also the nonlinear fundamental behavior of a number of different isolated structures and to derive new functionalities from this understanding, which then leads to new applications either by using a two- or three-dimensional array of such structures or by using a single isolated structure.First, we want measure the electric and magnetic near fields of a number of different sub-wavelength building blocks. The emphasis is on building blocks with novel functionalities; specifically, structures which are suitable for polarization control and structures which show a nonlinear resonant response. Second, we want to investigate the transition from regularly oriented building blocks to those which are randomly distributed and, therefore, examine the effect of lattice modes on the resonances and thus on the functionality of the meta-material. Randomly arranged defects in an otherwise ‘perfect’ materials show interesting transmission phenomena which stem from ‘phase transitions’ between different transport regimes, i.e. from ballistic to diffusive to anomalous diffusive due to localization. Here, we have the means to directly visualize these phenomena. Third, we want to optimize isolated structures for the highest possible THz field localization in order to investigate the possibility to employ such structures for high field THz or nonlinear THz spectroscopic applications. Fourth, we would like to start expanding our so far two dimensional arrays of building blocks into the third dimension, by adding more and more layers of such two-dimensional arrays and to realize meta-materials which are so far not accessible.