URL: https://www.desy.de/news/events/index_eng.html/@@events-view
Breadcrumb Navigation
30.11.2016 / 10:00 / Hamburg, CFEL-bldg. 99, seminar room IV (O1.111)
CFFL Science SeminarIntensity dependence of high-order harmonic wavefronts
Emma Kueny (Université Paris Sud)
High-order harmonics are used in a wide range of applications as a tab-letop source of XUV radiation. They are produced by nonlinear interac-tion of an intense infrared laser with gas atoms, and are characterized by a broadband spectrum containing only odd harmonics of the funda-mental wavelength with a constant intensity over a large spectral region. In order to achieve a high intensity when focusing the harmonics, their wavefront need to be flattened, and thus its formation understood. This master thesis presents single-shot high-order harmonics wavefronts recorded with a Hartmann XUV wavefront sensor, and aims at making a step forward the comprehension of this wavefront by first analyzing its dependence on the infrared intensity, then by looking at three individual harmonics. These first results mostly show an evolution of the diver-gence. Finally, these measurements permitted to optimize the refocus-ing optics to improve the wavefront, therefore obtaining a smaller and more intense focal spot for the applications using the harmonics.
