Our research interests are related to the theory of ultrafast processes in atoms, molecules and nanostructures induced, observed and controlled by ultrashort intense laser pulses. Electric field strengths of such laser pulses can exceed those of the Coulomb fields within an atom or molecule while the pulse durations are as short as a few femtoseconds (10^-15 s) or even shorter in the attosecond regime (1 as = 10^-18 s). Laser frequencies range from the far-infrared through the optical to the soft x-ray region. Recent results of our research include:

A New Set of Asymmetry Parameters
Asymmetries in photoelectron emission contain information about quantum interference effects. A set of generalized asymmetry parameters provides a new tool for the analysis of ionization of atoms in superposition states by ultrashort intense laser pulses ... read more.

Excitation in Bicircular Pulses
The excitation of atoms in bicircular pulses depends on the relative helicity of the two pulses and reveals interesting features such as higher-order Raman processes ... read more.

Central Frequency of Few-Cycle Pulses
We have analyzed the effect of the shift of the central frequency between the electric field and the vector potential in few-cycle pulses ... read more.

Isolated Circularly Polarized Attosecond Pulses
Two schemes to generate isolated attosecond pulses of pure circular polarization have been proposed theoretically. The control over the polarization has been recently demonstrated by our collaborators ... read more.

Delayed Resonant Two-Photon Ionization
We have proposed how the attosecond streaking camera technique can be used to retrieve time delays in resonant two-photon ionization ... read more.

Our research activities are supported by the National Science Foundation, the Department of Energy and the Air Force Office of Scientific Research.

We frequently utilize in our work the Summit supercomputer, which is a joint effort of the University of Colorado Boulder, the University of Colorado Denver and the National Center of Atmospheric Research.