A5046430629- Laser Material Processing Techniques
- Plasmonic and Surface Plasmon Research
- Molecular Junctions and Nanostructures
- Laser-Ablation Synthesis of Nanoparticles
- Gold and Silver Nanoparticles Synthesis and Applications
- Force Microscopy Techniques and Applications
- Laser-induced spectroscopy and plasma
- Near-Field Optical Microscopy
- Magnetic properties of thin films
- Ocular and Laser Science Research
- Nonlinear Optical Materials Studies
- Surface and Thin Film Phenomena
- Photonic Crystals and Applications
- Photonic and Optical Devices
- Chalcogenide Semiconductor Thin Films
- Nanofabrication and Lithography Techniques
- Fluid Dynamics and Thin Films
- Nanomaterials and Printing Technologies
- Silicon Nanostructures and Photoluminescence
- Surface Roughness and Optical Measurements
- Thin-Film Transistor Technologies
- Physics of Superconductivity and Magnetism
- Integrated Circuits and Semiconductor Failure Analysis
- Transition Metal Oxide Nanomaterials
- 2D Materials and Applications
University of Konstanz
2014-2024
Işık University
2006
Center for NanoScience
2005
Ludwig-Maximilians-Universität München
2005
Fraunhofer Institute for Mechanics of Materials
2000-2005
IBM Research - Almaden
1993
Hexagonally closed packed monolayers of colloids have found more and applications, e.g. as lithographic masks. The are usually produced with the help a self-organizing process where suspension is applied to desired substrate left dry. This method requires good wettability smoothness substrate, which severely limits number possible substrates. We present new for application colloid almost any surface these difficulties circumvented. At first fabricated on glass substrates afterwards floated...
Flat gold nanostructures on inert substrates like glass or graphite were illuminated by single intensive laser pulses with fluences above the melting threshold. The liquid structures produced in this way are far from their equilibrium shape, and a dewetting process sets in. On time scale of few nanoseconds, contracted toward sphere. During contraction, center mass moved upward, which could lead to detachment droplets surface due inertia. resulting velocities order 10 meters per second for...
The nonlinear thermal behavior of laser-heated gold nanoparticles in aqueous suspension is determined by time-resolved optical spectroscopy and x-ray scattering. can be excited transiently to high lattice temperatures owing their large absorption cross-section slow heat dissipation the surrounding. A consequence observation expansion, changed transmission, vapor bubble formation or particle melting. transfer equations are solved for two limiting cases pulses shorter longer than...
Colloid monolayer lithography is briefly reviewed and demonstrated to be a powerful alternative technique for the nanostructuring of surfaces. The Figure shows colloid viewed through TEM grid used transport desired substrate. together form lithographic mask that can later removed leave, example, pattern deposited gold dots.
We report on a method that allows the nanostructuring of surfaces with intense laser pulses. For this purpose isolated polystyrene spheres diameters in order wavelength were deposited silicon or glass surface. Illumination short and ultrashort pulses produced holes underneath these particles. Calculations field near particles make clear geometrical optics, is, focusing by spherical lens, as well near-field effects, contribute to size shape holes. This technique can be utilized for parallel...
Monolayers of colloidal particles formed in a self-organizing process upon drying suspension are used as lithographic masks. After deposition thin metal layer, the mask is detached from surface. The resulting surface examined with optical, scanning electron, and atomic force microscopes. In addition to well-known triangular structures, which reflect gaps hexagonal arrangement particles, we observed following additional features: hillocks (nano-dots) found just below nano-rings around...
Abstract The high field strength of femtosecond laser pulses leads to nonlinear effects during the interaction with condensed matter. One such effect is ablation process, which can be initiated below threshold common thermal if excitation are sufficiently short. This structure formation, anisotropic because polarization properties near and result in pattern sizes resolution limit light. These explored by temporally resolved scattering methods post‐mortem analysis show non‐thermal nature this...
Plasmonic resonances in metallic nano-triangles have been investigated by irradiating these structures with short laser pulses and imaging the resulting ablation melting patterns. The triangular gold were prepared on Si substrates had a thickness of 40 nm side length ca. 500 nm. Irradiation was carried out single femtosecond picosecond at wavelength 800 nm, which excited higher order plasmon modes triangles. distribution as well local small parts nanostructures reflect regions large...
We present a method for imaging the optical near-fields of nanostructures, which is based on local ablation smooth silicon substrate by means single, femtosecond laser pulse. At those locations, where field enhancement due to nanostructure large, material removed. The resulting topography, imaged scanning electron or atomic force microscopy, thus reflects intensity distribution caused at surface. With this one avoids possible distortion presence probe tip, and reaches resolution few...
Nanosecond pulsed two-beam laser interference is used to generate two-dimensional temperature patterns on a magnetic thin film sample. We show that the original domain structure of [Co/Pd] multilayer changes drastically upon exceeding Curie by thermal demagnetization. At even higher temperatures system irreversibly changed. In this area no out-of-plane magnetization can be found before and after subsequent ac-demagnetization. These findings are supported numerical simulations using...
In an attempt to design molecular optoelectronic switches functioning in junctions between two metal tips, we synthesized a set of photochromic compounds by extending the π-system 1,2-bis-(2-methyl-5-formylfuran-3-yl)perfluorocyclopentene through suitable coupling reactions involving formyl functions, thereby also introducing terminal groups with binding capacity gold. Avoiding presence gold-binding sulphur atoms photoreactive centre, as they are present frequently used analogous thienyl...
The quantitative determination of the strength near-field enhancement in and around nanostructures is essential for optimizing using these structures applications. We combine Gaussian intensity distribution a laser profile two-photon-polymerization SU-8 to suitable tool experimental measurement nanostructure. Our results give feedback obtained by finite-difference time-domain (FDTD) simulations. under investigation are gold nanotriangles on glass substrate with 85 nm side length thickness 40...
Metallic point contacts (MPCs) with dimensions comparable to the Fermi wavelength of conduction electrons act as electronic waveguides and might operate plasmon transmitters. Here we present a correlated study optical conductance response MPCs under irradiation laser light. For elucidating role surface polaritons (SPPs), integrate line gratings into leads that increase SPP excitation efficiency. By analyzing spatial, polarization, time dependence, identify two contributions attribute...
In this work we report the application of two and three-beam single pulse laser interference lithography to thin polymer films poly(trimethylene terephthalate) (PTT). By irradiating sample surface with temporary spatially overlapped pulses from or three coherent beams changing angles incidence, have accomplished fabrication large-area micro submicrogratings as well submicrometric cavities arranged in a hexagonal lattice. The characterization structures real space by atomic force microscopy...
In this review we consider the development of optical near-field imaging and nanostructuring by means laser ablation since its early stages around turn century. The interaction short, intense pulses with nanoparticles on a surface leads to laterally tightly confined, strongly enhanced electromagnetic fields below nano-objects, which can easily give rise nanoablation. This effect be exploited for structuring substrate surfaces length scale well diffraction limit, one two orders smaller than...