https://doi.org/10.1051/epjconf/20134102024
Temporal and spectral evolution of an interrupted virtual single-photon transition: creation of optical gain and loss
1 Physics Department, ETH Zurich, CH-8093 Zürich, Switzerland
2 Departamanto de Química, Universidad Autónoma de Madrid, ES-28049 Madrid, Spain
3 Max Planck Institute for the Physics of Complex Systems, D-01187 Dresden, Germany
We examine the optical response of a virtual dipole transition of a quantum mechanical two-level system (TLS). In the case of off-resonant excitation the time-integrated dipole response (TIDR) is expected to be zero, which corresponds to transparency of the system with respect to the exciting pulse. Our new time-frequency representation reveals that even for a zero TIDR there are positive and negative contributions included in the response. Furthermore, we present a way to access these contributions by using a second electromagnetic field, which interrupts the temporal evolution of the dipole response. The theoretical results are confirmed by attosecond transient absorption spectroscopy in helium (He).
© Owned by the authors, published by EDP Sciences, 2013
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
