Physical Review A
Transmission of an isolated attosecond pulse in a strong-field dressed atom
Adrian Nikolaus Pfeiffer, Stephen R. Leone
Abstract
The optical properties of matter can be manipulated by coupling a strong field to an optical transition. The concepts of Autler-Townes splitting and electromagnetically induced transparency, where a control field manipulates the transmission of a probe field, have recently been extended to control the transmission of x rays. The use of a strong femtosecond pulse to control the transmission of an isolated attosecond extreme ultraviolet or soft x-ray pulse opens a new field of investigation, since the duration of the probe pulse is only a fraction of one optical cycle of the control pulse. In this paper a three-state model beyond the rotating wave approximation is formulated that treats the attosecond pulse as an initial value problem in the time domain. Two effects for spectroscopic measurements are elucidated: first the absorption profile of the attosecond pulse is split into multiple lines rather than a doublet in the high-field regime, and second the transmission of the attosecond pulse depends on the relative timing within the optical cycle of the control pulse. An analytical treatment is carried out in the time domain in contrast to the more common approach in the frequency domain. This is appropriate for the field of attosecond physics where the main interest lies in the time evolution of the fields, rather than spectroscopic studies.