Electronic dynamics in molecules and atoms takes place on the attosecond timescale. For the observation of such processes, measurement techniques with attosecond resolution are needed. High-harmonic generation (HHG) in gas medium provides an ultrashort light source on the attosecond timescale for observing, understanding and controlling light-induced process on this scale with the necessary time resolution. To be able to use these attosecond pulses to measure electron dynamics, they have to be characterized. For this characterization, the XUV spectrum is extremely important. The XUV spectrum not only contains the information about the photon energies of the pulses, but also temporal information such as the difference between a single isolated attosecond pulse or an attosecond pulse train. The Light Wave Synthesizer 20 generates intense femtosecond pulses with a peak power of 16 TW and a spectrum spanning over the region from 580 to 1000 nm. This allow one to generate attosecond pulses based on HHG in gas medium with 100 eV photon energy and up to 20 nJ pulse energy. The generated attosecond pulses can be observed with a photodiode to measure the energy, an XUV CCD used as a profiler and an XUV flat-field spectrometer. The detector of the flat-field spectrometer is an XUV CCD which records the diffracted beam from a grating. Hence, a certain pixel of the camera shows the intensity for a certain range of photon energies. However, the calibration from pixel to energy is not always fixed due to e.g. the alignment of the spectrometer. This pixel to photon energy calibration can be done either by using the harmonic peaks in the XUV spectra or theoretical analyses of the spectrometer structure. In this thesis, both methods are investigated and the results are in good agreement. Due to the analytical calibration has a lower error and faster to do, future measurements can be evaluated with the analytical method.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:umu-165564 |
| Date | January 2019 |
| Creators | Wu, Xiuyu |
| Publisher | Umeå universitet, Institutionen för fysik |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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