Spectral phase measurement of a Fano resonance using tunable attosecond pulses

• Published in: Nature communications Vol. 7; no. 1; pp. 10566 - 6
• Main Authors: Kotur, M., Guénot, D., Jiménez-Galán, Á, Kroon, D., Larsen, E. W., Louisy, M., Bengtsson, S., Miranda, M., Mauritsson, J., Arnold, C. L., Canton, S. E., Gisselbrecht, M., Carette, T., Dahlström, J. M., Lindroth, E., Maquet, A., Argenti, L., Martín, F., L’Huillier, A.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 18.02.2016; Nature Publishing Group; Nature Portfolio
• Subjects: 140/125; 140/146; 639/766/36/2796; 639/766/483/1139; Atom and Molecular Physics and Optics; Atom- och molekylfysik och optik; Atom- och molekylfysik och optik (Här ingår: Kemisk fysik, kvantoptik); Chemical Sciences; Fysik; Humanities and Social Sciences; Infrared radiation; Ionization; multidisciplinary; Natural Sciences; Naturvetenskap; Physical Sciences; Physics; Resonance; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms10566

Electron dynamics induced by resonant absorption of light is of fundamental importance in nature and has been the subject of countless studies in many scientific areas. Above the ionization threshold of atomic or molecular systems, the presence of discrete states leads to autoionization, which is an interference between two quantum paths: direct ionization and excitation of the discrete state coupled to the continuum. Traditionally studied with synchrotron radiation, the probability for autoionization exhibits a universal Fano intensity profile as a function of excitation energy. However, without additional phase information, the full temporal dynamics cannot be recovered. Here we use tunable attosecond pulses combined with weak infrared radiation in an interferometric setup to measure not only the intensity but also the phase variation of the photoionization amplitude across an autoionization resonance in argon. The phase variation can be used as a fingerprint of the interactions between the discrete state and the ionization continua, indicating a new route towards monitoring electron correlations in time. Resonant absorption of light in atoms can lead to autoionization, whose probability exhibits a Fano intensity profile. Here, the authors use attosecond pulses and weak infrared radiation to study the phase variation of the photoionization amplitude across an autoionization resonance in argon.