Characterization of Attosecond Pulses Driven by Few-Cycle Lasers

• Main Authors: Huang, Po-Yao, 黃柏堯
• Other Authors: Chen, Ming-Chang
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/y39292

碩士 === 國立清華大學 === 光電工程研究所 === 107 === The generation of ultrashort pulses provides an avenue for exploring the fast-evolving phenomena in nature. Since recent advancement in ultrafast optics has pushed the duration of laser pulses from femtosecond to attosecond regime, even electron dynamics in atomic systems can be tracked by pump-probe measurement technique. However, the attosecond pulses produced from high-order harmonic generation (HHG) inherently possess attochirps which affect the pulse duration of generated attosecond pulses. Complete characterization of arbitrary attosecond pulses, therefore, is indispensable not only to determine but also to further increase the temporal resolution for time-resolved measurements. In this thesis, we characterized the temporal profile of extreme-ultraviolet (EUV) attosecond pulses by using the photoelectron streaking technique where the generated EUV attosecond pulse is converted to its electron replica through photoionization in the presence of a delayed infrared (IR) dressing laser field. After properly adjusting the delay between attosecond pulses and dressing laser fields, a streaked spectrogram of energy as a function of delay can be obtained. By feeding this streaked spectrogram into an iterative algorithm, the temporal information about both EUV attosecond pulses and IR dressing fields can be extracted simultaneously and consequently the temporal profile of these pulses can be fully reconstructed. This measurement technique is essential for attosecond science.