This technology describes the continuous buildup welding of thin rod-shaped materials (especially thin wires) onto a substrate using laterally coupled laser radiation. The wire is positioned in relation to the substrate material in such a way that both meet at an sharp angle. In this contact area, both materials are illuminated with a pre-shaped, focused and pulsed laser beam melting the thin wires only partially.
Researchers at the Institute of Nanophotonics Göttingen e.V. have developed a microstructuring process for commercial titanium-containing glasses by excimer laser irradiation. By irradiating commercial TiO2-containing glasses in ambient air with an excimer laser (ArF laser with 193nm wavelength and 20ns pulse duration), microstructures can be generated and thus the surface darkened.
This novel device enables the cleaning of water in a pipe system into which an irradiation unit is inserted via an insertion module with flange connection. The surrounding water is then irradiated across the entire cross-section with a blue laser as it passes through the quartz tube, killing any microorganisms it contains.
Laser processing head for direction-independent build-up welding
Scientists at the Laser Zentrum Hannover have developed a welding head for laser-assisted or laser-based buildup welding with a coaxial arrangement of the weld deposit feed. Several individual beams are bundled in a focal point below the welding material supply. In general, all meltable materials (e.g. metals, glass or polymers) can be processed with this system.
A force- and vibration-free joining process for metal and thin glass was developed at the Laser Zentrum Hannover e.V.. In this process, the thin glass is pressed onto the metal substrate with as little contact as possible and the two joining partners are heated by means of laser radiation, resulting locally in a partly seamless, partly form-fit connection.
A stretched flexible hollow fiber is proposed as a waveguide in high-energy pulse compressors. This approach leads to superior straightness virtually independent of the fiber length. It is particularly well suited for fibers with inner diameters much larger than the wavelength, where the main limitation for the fiber length is losses due to undesired fiber bending.
Nonlinear crystals are used for frequency conversion of lasers. With the help of this technology the radiation hardness in the UV range could be increased and at the same time the laser construction could be simplified, because the crystals do not have to be heated permanently. In particular, the present patent concerns the nonlinear family of hygroscopic borates (LBO, BBO, CLBO), which are particularly suitable for the generation of photons in the ultraviolet (UV) spectral range.
A method has been found for freeform shaping of optical surfaces via a stress-induced viscous deformation of glass plates. Fused silica substrates can be deformed by covering them with substoichiometric silicon oxide followed by a laser patterning process and an annealing step.
The newly developed method provides a fast and efficient way for producing gratings - by ablation of small amounts of material - on glass surfaces. Consequently, the economic labeling of glass with patterns causing diffraction becomes possible. These patterns shine in different colors if observed from different angles.
Z-shifter for diffractive labeling of curved surfaces
The newly developed method allows for shifting of the interference plane in the Z-direction during diffractive marking of surfaces with a grating interferometer. Plane-parallel plates are used, the rotation of which introduces a beam offset that causes a Z-shift of the interference plane when the beams are combined.
The newly developed method only requires the detection of movement directions of light patterns (speckles) for the determination of refractive error of the human eye. The subjective evaluation of the effect of the corrective lenses by the patient can thus be reduced to a simple question (e.g. right/left).
Superimposed CGHs on metals using laser ablation of diffractive pixels
A special interference process allows the fabrication of computer-generated holography (CGH) as carrier of information which can’t be recognized with the human eye. The CGHs consist of N * M pixels which, when illuminated with coherent light, generate an imagine with the same pixel dimensions in a Fourier plane. Several CGHs can be written on the same area. When illuminated with the same coherent reading beam, they appear separately in different directions (diffraction orders).
This innovative approach combines the two known methods of Laser Induced Backside Wet Etching (LIBWE) and Stimulated Emission Depletion (STED) to realize laser based material modifications below the diffraction limit. This is especially useful for precision laser modifications of transparent materials.
Unintentional deformation of optical substrates is a common issue in optics technology. The mechanical stress in thin films can have a deleterious effect on the quality of the optical components by deforming the underlying substrate. This patent describes a figure correction method bases on stresses induced by irradiation of glass substrates with an excimer laser.
Preconnection element for the protection of hollow fibers
This invention is a further development to the flexible hollow fiber for pulse compression which was also developed at the Institut für Nanophotonik Göttingen e.V. (see Ref.: MM-2010-LLG). When laser light is coupled into hollow fibers, the problem often arises that parts of the light distribution can penetrate the thin wall (50-300 μm) and damage it by erosion/ablation/melting. This preconnection element provides a solution approach.
The technology describes a method to fabricate a virtually ideal wave guide for spectral broadening and high damage threshold. This is achieved by embedding a flexible hollow fiber at ideal straightness in a stretched stat in a thermally conductive solid medium, combining high transmission and high robustness even when high laser powers are coupled in. It is an advancement to the flexible hollow fiber developed at the Institut für Nanophotonik Göttingen e.V. (see reference MM-2010-LLG).
The present invention suggests a novel laser-based system, which allows for a contact-free measurement of deformations/strains. The system can be easily implemented in complex testing setups and yields enhanced performance characteristics.
X-ray targets for generating x-ray radiation from a waveguide
These innovative multilayer x-ray targets allow the generation of x-ray radiation based on direct emission of spontaneous x-rays into waveguide modes. Photons are generated by electron impact onto a structured anode target, which is formed as an x-ray waveguide or waveguide array.
Efficient manufacturing of undercut or vaulted nano-scaled surfaces
Presented here is a very simple process of manufacturing undercut respectively vaulted surfaces with nano-scaled structures. Especially for cell culture and implantologic purposes those structures are of great interest. Compared to conventional techniques rapid processing of large surface areas is possible.
Ultra-stable cryostage for cryo fluorescence microscopy applications
The invention relates to a sample holder to be used in cryo fluorescence microscopes or to simply and cost effectively upgrade a room temperature fluorescence microscope. The holder solves existing problems regarding thermal and mechanical stability of the sample and allows for a localization accuracy of a few hundred Angstroms.
