Andreas Tünnermann

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Optical side-effects of fs-laser treatment in refractive surgery are investigated by means of a model eye. We show that rainbow glare is the predominant perturbation, which can be avoided by randomly distributing laser spots within the lens. For corneal applications such as fs-LASIK, even a regular grid with spot-to-spot distances of ~3 µm is sufficient to(More)
Coherent Diffraction Imaging is a technique to study matter with nanometer-scale spatial resolution based on coherent illumination of the sample with hard X-ray, soft X-ray or extreme ultraviolet light delivered from synchrotrons or more recently X-ray Free-Electron Lasers. This robust technique simultaneously allows quantitative amplitude and phase(More)
The strong-field process of high-harmonic generation is the foundation for generating isolated attosecond pulses 1 , which are the fastest controllable events ever induced. This coherent extreme-ultraviolet radiation has become an indispensable tool for resolving ultrafast motion in atoms and molecules 2,3. Despite numerous spectacular developments in the(More)
The ability to efficiently transmit and rapidly process huge amounts of data has become almost indispensable to our daily lives. It turned out that all-optical networks provide a very promising platform to deal with this task. Within such networks opto-optical switches, where light is directed by light, are a crucial building block for an effective(More)
—Using an AlGaAs–GaAs waveguide structure with a six-stack InAs–InGaAs " dots-in-a-well " (DWELL) gain region having an aggregate dot density of approximately 8 10 11 cm 2 , an optical gain of 18 dB at 1300 nm has been obtained in a 2.4-mm-long amplifier at 100-mA pump current. The optical bandwidth is 50 nm, and the output saturation power is 9 dBm. The(More)
A concept for a low-loss all-reflective cavity coupler is experimentally demonstrated at a wavelength of 1064 nm. A 1450-nm period dielectric reflection grating with a diffraction efficiency of 0.58% in the - 1st order is used in the 2nd-order Littrow configuration as a coupler to form a cavity with a finesse of 400. The application of such reflective(More)
The light scattering of rough metallic surfaces with roughness levels ranging from a few to several hundred nanometers is modeled and compared to experimental data. Different modeling approaches such as the classical Rayleigh-Rice vector perturbation theory and the new Generalized Harvey-Shack theory are used and critically assessed with respect to ranges(More)
We report on the experimental observation of novel defect-free surface modes predicted theoretically for modulated photonic lattices [I. L. Garanovich et al., Phys. Rev. Lett. 100, 203904 (2008)10.1103/PhysRevLett.100.203904]. We generate the linear surface modes in truncated arrays of periodically curved optical waveguides created in fused silica by a(More)
Dynamic localization is the suppression of the broadening of a charged-particle wave packet as it moves along a periodic potential in an a.c. electric field 1–3. The same effect occurs for optical beams in curved photonic lattices, where the lattice bending has the role of the driving field, and leads to the cancellation of diffraction 4–8. Dynamic(More)
We study propagation of light beams in two-dimensional photonic lattices created by periodically curved waveguide arrays. We demonstrate that by designing the waveguide bending, one can control not only the strength and sign of the beam diffraction, but also to engineer the effective geometry and even dimensionality of the two-dimensional photonic lattice.(More)