Till Leißner

Till Leißner
University of Southern Denmark | SDU · Mads Clausen Institute

Dr. rer. nat.

About

31
Publications
3,300
Reads
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375
Citations
Introduction
My current research focus is about the nanofabrication of photonic and plasmonic components utilizing Neon Ion Beam Lithography (NIBL), Helium ion microscopy and Ga focused ion beam. Furthermore I am studying organic-plasmonic hybrid systems using time-resolved photoluminescence spectroscopy.
Additional affiliations
January 2016 - December 2018
University of Southern Denmark
Position
  • Professor (Assistant)
January 2015 - December 2015
University of Southern Denmark
Position
  • PostDoc Position
January 2014 - December 2014
University of Southern Denmark
Position
  • PostDoc Position
Education
January 2009 - June 2013

Publications

Publications (31)
Article
In this work the mutual coupling and coherent interaction of propagating and localized surface plasmons within a model-type plasmonic assembly is experimentally demonstrated, imaged and analyzed. Using interferometric time-resolved photoemission electron microscopy the interplay between ultrashort surface plasmon polariton wave packets and plasmoni...
Article
Full-text available
Understanding the impact of lateral mode confinement in plasmonic waveguides is of fundamental interest regarding potential applications in plasmonic devices. The knowledge of the frequency-wave vector dispersion relation provides the full information on electromagnetic field propagation in a waveguide. This Letter reports on the measurement of the...
Article
Full-text available
Plasmonic wave packet propagation is monitored in dielectric-loaded surface plasmon polariton waveguides realized from para-hexaphenylene nanofibers deposited onto a 60 nm thick gold film. Using interferometric time resolved two-photon photoemission electron microscopy we are able to determine phase and group velocity of the surface plasmon polarit...
Article
The spatiotemporal evolution of a SPP wave packet with femtosecond duration is experimentally investigated in two different plasmonic focusing structures. A two-dimensional reconstruction of the plasmonic field in space and time is possible by the numerical analysis of interferometric time-resolved photoemission electron microscopy data. We show th...
Article
Full-text available
In an interferometric time-resolved photoemission electron microscopy (ITR-PEEM) experiment, the near-field associated with surface plasmon polaritons (SPP) can be locally sensed via interference with ultrashort laser pulses. Here, we present ITR-PEEM data of SPP propagation at a gold vacuum interface recorded in a counter-propagating pump-probe ge...
Article
Full-text available
The dispersive properties of short-range surface plasmon polaritons are investigated at the buried interfaces in vacuum/Au/fused silica and vacuum/Au/SiO2/Si multilayer systems for different gold film thicknesses of up to 50 nm using two-photon photoemission electron microscopy. The experimental data agrees excellently with results of transfer matr...
Article
Single dibenzoterrylene (DBT) molecules in anthracene nanocrystals have been shown to emit single photons without blinking, bleaching or spectral diffusion. Efficient integration of these molecules into photonic circuits will pave the way toward the realization of quantum optical networks. Here, we incorporate anthracene nanocrystals containing sin...
Article
The field of organic field-effect transistors (OFETs) has matured over the past two decades and devices with charge carrier mobilities of several cm²/Vs have been demonstrated. Nevertheless, to enter commercial products, the operational stability of OFET technology also needs to be addressed. Herein, two potential degradation mechanisms occurring i...
Article
Au nanoparticles (NPs) decorated heterogeneous TiO2 catalysts are known to be effective in the degradation of various organic pollutants. The photocatalytic performance of such Au-TiO2 structures remarkably depends on size, morphology and surface coverage of Au NPs decorating TiO2. Here we propose an effective way of preparing highly active Au nano...
Article
We present an advanced experimental setup for time-resolved photoemission electron microscopy (PEEM) with sub-20 fs resolution, which allows for normal incidence and highly local sample excitation with ultrashort laser pulses. The scheme makes use of a sample rear side illumination geometry that enables us to confine the sample illumination spot to...
Article
Efficiency-limiting degradation of organic compounds is one of the main bottlenecks suppressing rapid commercialization of organic optoelectronic devices. Herein, degradation mechanisms of N,N'-di-1-naphthalenyl-N,N'-diphenyl [1,1':4',1'':4'',1‴-quaterphenyl]-4,4‴-diamine (4P-NPD) — a blue emitter, host for triplet harvesting and hole transport mat...
Article
Full-text available
Multimode waveguiding in the visible and near-ultraviolet spectral regime is observed and characterized in thermally grown SiO2 layers on silicon using photoemission electron microscopy (PEEM). Comparison with finite-element-method simulations allows identifying order and character of the attenuated modes. Real-time investigations on mode propagati...
Article
Full-text available
Mode character and mode dispersion of sub-60-nm-thick polymethyl methacrylate dielectric-loaded surface plasmon-polariton waveguides (DLSPPWs) are investigated using photoemission electron microscopy and finite element method simulations. Experiment and simulation show excellent agreement and allow identifying a crossover from single-mode to multi-...
Article
Gold is the most commonly used plasmonic material, however soft and prone to mechanical deformations. It has been shown that the durability of gold plasmonic substrates can be improved by applying a protective diamond-like carbon (DLC) coating. In this work, we investigate the influence of such protective layers on plasmonic interactions in organic...
Article
Micro- and nano-scale systems with defined active elements acting as local surface plasmons polariton (SPP) sources are crucial for the development of future plasmonic circuits. We demonstrate SPP excitation by fluorescent light from crystalline organic para-hexaphenylene nanofibers deposited on a dielectric/metal surface. We characterize the SPPs...
Article
The device performance of organic transistors is strongly influenced by the charge carrier distribution. A range of factors effect this distribution, including injection barriers at the metal-semiconductor interface, the morphology of the organic film, and charge traps at the dielectric/organic interface or at grain boundaries. In our comprehensive...
Conference Paper
Recent research on hybrid plasmonic systems has shown the existence of a loss channel for energy transfer between organic materials and plasmonic/metallic structured substrates. This work focuses on the exciton-plasmon coupling between para-Hexaphenylene (p-6P) organic nanofibers (ONFs) and surface plasmon polaritons (SPPs) in organic/dielectric/me...
Article
Full-text available
In this letter we show that the optical response of organic nanofibers, grown from functionalized para-quaterphenylene molecules, can be controlled by forming organic-plasmonic hybrid systems. The interaction between nanofibers and supporting regular arrays of nanostructures leads to a strongly enhanced second harmonic response. At the same time, t...
Conference Paper
Full-text available
In this work, enhancement of the second harmonic response of organic nanofibers deposited on encapsulated and robust plasmonic active substrate is experimentally demonstrated. Organic nanofibers grown from functionalized paraquaterphenylene (CNHP4) molecules have been transferred on lithographically defined regular arrays of gold nanostructures, wh...
Article
Full-text available
Two-photon photoemission electron microscopy (2P-PEEM) is used to measure the real and imaginary part of the dispersion relation of surface plasmon polaritons at different interface systems. A comparison of calculated and measured dispersion data for a gold/vacuum interface demonstrates the capability of the presented experimental approach. A syste...
Conference Paper
Full-text available
This paper considers a range of plasmonic-black-metal polarizers suitable for ultra-short pulses. The polarizers consist of a metal surface being nanostructured with a periodic array of ultra-sharp grooves with periods of 250-350 nanometers, and groove depths around 500 nanometers. The surfaces can be designed such that practically all incident lig...
Article
Full-text available
It has recently been demonstrated that adiabatic nanofocusing of light by gap-plasmon modes in ultra-sharp convex metal grooves can turn metallic surfaces with high reflectivity in the visible and near-infrared into excellent absorbers of light polarized perpendicular to the groove direction. Here we demonstrate that this effect can be used to desi...
Article
Full-text available
In this paper we demonstrate the realization of an autocorrelator for the characterization of ultrashort surface plasmon polariton (SPP) pulses. A wedge shaped structure is used to continuously increase the time delay between two interfering SPPs. The autocorrelation signal is monitored by non-linear two-photon photoemission electron microscopy. Th...
Article
Full-text available
The excitation of surface plasmon polaritons (SPP) at a gold–vacuum interface by femtosecond light pulses mediated by organic nanofiber-induced dielec-tric perturbations is observed using interferometric time-resolved photoemission electron microscopy. The experimental data are quantitatively reproduced by an-alytic simulations, where the nanofiber...
Article
The reversible photo- and thermally activated isomerization of the molecular switch 3-(4-(4-Hexyl-phenylazo)-phenoxy)-propane-1-thiol (ABT, short for AzoBenzeneThiol) deposited by self-assembly from solution on Au (111) was studied using laser-based photoelectron spectroscopy. Differences in the molecular dipole moment characteristic for the trans...
Conference Paper
Surface plasmon polariton (SPP) excitation at a gold-vacuum interface via 800 nm light pulses mediated by a periodic array of gold ridges is probed at high lateral resolution by means of photoemission electron microscopy (PEEM). We directly monitor and quantify the coupling properties as a function of the number of grating ridges and compare the PE...
Article
Simultaneous time-and energy-resolved two-photon photo-emission with nanometer resolution is demonstrated for the first time. We monitor the energy dependence of the decay dynamics of electron excitations in individual silver particles, which were deposited from a gas aggregation cluster source onto a silicon substrate. We show furthermore that the...

Projects

Projects (3)
Project
The first part of the project is characterization of biological samples, such as human kidneys and human skin at nanoscale, using Helium Ion Microscopy (HIM). The second part of the project will be the development of a method for correlative microscopy, firstly for HIM and confocal microscopy and then expanded to Optical Coherence Tomography (OCT), TiCo Raman, Scanning Electron Microscopy (SEM), confocal microscopy, Stimulated Emission Depletion (STED) microscopy and Coherent Anti-Stokes Raman Scattering (CARS) microscopy. The acquired methods can then be utilized to examine the same area with different microscopes. The last part of the project will include the development of an appropriate image analysis to enable the understanding and combination of the images acquired by correlative microscopy.
Project
A key opportunity in the border region are strong university hospitals on both German and Danish side (UKSH and OUH) as well as key R&D laboratories in modern imaging methods, which allow us to investigate microscopic changes in human cells that accompany cancer diseases. By combining new and complementary techniques, diagnostics is greatly improved and validated by the hospitals. The weakness so far has been missing x-border knowledge exchange between R&D organisations, hospitals and interested companies. The CellTom project will tackle this challenge, combine advanced techniques x-border and make them available intersectoral and throughout the program region. CellTom will initiate a virtual service center for biomedical imaging (VISION) that acts as a point of contact for interested R&D institutions, physicians and companies that take advantage in using the new microscopy methods. VISION will in addition be an innovation hub for regional medical technology companies. Later in the project, companies from the food industry should be connected. On the medium term, VISION should also be opened to other sectors. Altogether this will result in a knowledge leap in the program region and in sustainable innovation that generates new working places and new working force. The project is possible only in a cross-border cooperation, in which the partners add complementary techniques and expertise. BMO and MLL in Lübeck will contribute above state of the art optical technologies, while MCI in Sønderborg will provide a Helium Ion Microscope, which is unique in the region and beyond. The combination allows us to develop new and reliable diagnostic methods that enable physicians to check quickly - during surgery - whether a tumour has been completely removed. UKSH and OUH will validate this new technology. Moreover, the outcomes will benefit the entire program region via involvement of a geographically spread range of network partners that include hospitals, companies, cluster networks, and business development and technology transfer organizations. Finally, CellTom will also focus on establishing key know-how and transferring it from the medical area into the food industry and material science. Here innovative microscopic imaging methods are extremely relevant, too. Training of highly qualified personnel in the field of medical and imaging technology - a key factor for making the region competitive – will thus be emphasized.
Archived project