No description available.

This thesis describes the theory, development and applications of laser beam characterisation for industrial laser materials processing systems. Descriptions are given of novel forms of beam diagnostic systems and their integration into highly automated industrial tools. Work is also presented that has contributed to the new ISO standard on beam characterisation. Particular emphasis is given to excimer laser applications and UV micromachining.

A discharge pumped LC inversion type XeCl excimer laser was constructed, and its discharge and output were examined. A maximum output energy of 167 mJ was achieved, with an efficiency of 0.56%, using 60 psi of a gas composed of 0.56% HCl, 2.48% Xe, 48.48% He, and 48.48% Ne. The 308 nm laser output pulse had a fwhm of 20 ns and a peak power of 8.6 MW. When charged to 35 kV, the voltage inversion reached a peak of ~45 kV and dropped to zero in ~35 ns. The fwhm of the discharge current was 46 ns, with a peak current of 15.3 kA. The electron density in the discharge was measured using an infrared Michelson interferometer, and found to have a fwhm of 30 ns and a peak value of 12±5xl0¹⁴ cm⁻³. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

No description available.

No description available.

Thesis (M.S.)--Rochester Institute of Technology, 1991. / Typescript. Includes bibliographical references.

Thesis (Ph. D.)--Washington State University, May 2010. / Title from PDF title page (viewed on June 22, 2010). "Department of Physics and Astronomy." Includes bibliographical references.

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 7 uppsatser.

Fabrication of a 3D structure and surface texture using excimer laser mask projection ablation processes typically requires the machine operator to develop a specific NC part program for the desired structure geometry, and also incorporate appropriate machine parameters to achieve the desired surface finish. The capability of the laser ablation process could therefore be significantly improved by developing a CAD/CAM system that automatically generates the NC part program using the 3D information of the CAD model of the desired structure. Accordingly, the focus of this research was to develop such a system that is, an effective CAD/CAM system specifically for excimer laser mask projection micromachining tools. To meet these requirements, a unique combination of commercially available systems was used to develop the new CAD/CAM system. The systems used comprised of a computer aided, feature based parametric design system (SolidWorks), together with its extended programming capabilities based on Automated Programming Interface (API) functions for Windows applications, and Visual Basic (VB) 6.0 programming utilities. The system's algorithms use a novel methodology to extract the 3D geometry of a microstructure. Two different techniques have been developed to extract the 3D data. First, where 3D geometry information from a CAD model was defined as a Stereolithography (STL) file, and second, where this information has been contained in a set of bit-map (BMP) files that represent a sliced or layered structure of a CAD model. Based on this, first an algorithm to create NC part programs to support Step-and-repeat micromachining technique was developed and then successfully extended to be applicable for another commonly used micromachining method, Workpiece-Dragging technique. The systems algorithms for both techniques are based on the raster-colour programming technique, resulting in substantially reduced mathematical complexity and computational time. This is the first time this approach has been used to support direct conversion of 3D geometry from a CAD model into an NC part program compatible with the excimer laser CNC controller. 2D mathematical models for controlling edge and stitching errors were also implemented in the system. An additional technique, named as 'Common Nest' has been developed with the aim to enable automatic NC part programming when microstructure design to be completed successfully, requires use of multiple complex mask patterns as a projection tool instead of just a single square aperture. The effectiveness of the system was verified by NC part program generation for several 3D microstructures and subsequent machining trials using polycarbonate (PC) and Polyethylene terephthalate (PET), and optimised processing parameters. Excellent agreement was obtained between the laser machined geometries and the microstructure CAD models. The Laser Scanning Confocal Microscope (LSCM) measured the lateral dimensions tolerance of 2m. The system was also successfully applied for a practical micro-engineering application, for the development of a microfluidics cell transportation device.

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 6 uppsatser.