title: Diffractive/refractive (hybrid) UV-imaging system for minimally invasive metrology: design, performance, and application experiments.
abstract: A hybrid imaging system was developed to enable the application of laser-based measurement techniques like UV laser-induced fluorescence in near-production engines with small access ports. For this task, wide-angle characteristics and high lens speed are required in combination with small engine-bound optics able to survive in harsh environmental conditions. Our approach combines a simple and robust access lens with refractive/diffractive (hybrid) imaging stages away from the engine that are customized for individual wavelength bands. We give a detailed insight into the design strategy, including the integration of diffractive optics and the performance of the system with analysis of the modulation transfer function (MTF), lens speed, and stray light. Finally, results from applications in an actual engine are shown.
authors.affiliation: Institut für Technische Optik (ITO), University of Stuttgart, Stuttgart, Germany. reichle@ito.uni‐stuttgart.de
authors.forename: René
authors.initials: R
authors.lastname: Reichle
authors.forename: Christof
authors.initials: C
authors.lastname: Pruss
authors.forename: Christopher
authors.initials: C
authors.lastname: Gessenhardt
authors.forename: Christof
authors.initials: C
authors.lastname: Schulz
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Osten