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Free keywords:
Physics, Chemical Physics, physics.chem-ph, Physics, Optics, physics.optics
Abstract:
Two- and multi-dimensional spectroscopy is used in physics and chemistry to
obtain structural and dynamical information that would otherwise be invisible
by the projection into a one-dimensional data set such as a single emission or
absorption spectrum. Here, we introduce a qualitatively new two-dimensional
spectroscopy method by employing the carrier-envelope phase (CEP). Instead of
measuring spectral vs. spectral information, the combined application of
spectral interferometry and CEP control allows the measurement of otherwise
inseparable temporal events on an attosecond time scale. As a specific example,
we apply this general method to the case of attosecond pulse train generation,
where it allows to separate contributions of three different sub-cycle electron
quantum paths within one and the same laser pulse, resulting in a better
physical understanding and quantification of the transition region between
cutoff and plateau harmonics. The CEP-dependent separation in time between two
full-cycle spaced attosecond pulses was determined to modulate by (54 +/- 16)
attoseconds.
