Current Research Emphasis

I moved into the field of the interaction of intense lasers with atoms and molecules since 2002.  We have published 30 papers in the period of 2002-2006.

   I am pushing two general directions with intense short pulse lasers. The first one is attosecond physics, including issues related to its technology and applications. The other is time-resolved chemical imaging. This latter one is to study the possibility of using lasers to image the structure of matter as it undergoes transitions at the time scale of femtoseconds or picoseconds, as in a chemical reaction. 

  More discussions on the recent works can be found  here.

Research Expertise

   In my career, I have carried out research in a number of different subfields in Atomic, Molecular and Optical Physics.  They include:

1. many-body effect in photoionization of atoms (1970's)

2. relativistic many-body perturbation theory (1970's)

3. doubly excited states of helium (1970's, 1980's)

4. classification of triply excited states of atoms (1990's)

5. charge transfer in ion-atom collisions at intermediate energies (1970's to 1990's)

6. electron emission in high-energy ion-atom collisions (1990's)

7. hyperspherical coordinates for general three-body systems (1980's, 1990's)

8. interactions of atoms and molecules with intense lasers (after 2002)

9. attosecond physics (after 2004)

10. time-resolved chemical imaging with lasers (after 2006)

 My research tends to divide into two categories-- theories that are used to interpret experiments, especially experiments carried out at Kansas State University, and theories that I consider of fundamental importance. In the first category, my work was used to interpret photoionization cross sections of atoms under synchrotron radiation and charge transfer cross sections in ion-atom collisions. These two fields were considered to be "hot" fields in the 1970's and 1980's respectively. Both fields became quite mature at the end of 1990's and research funding for both fields began to diminish.  Our experimental group and myself decided to move on to new directions involving short intense laser fields at around 2002 after a careful planning.

    In the second category, my theoretical work addresses fundamental issues. In particular, the quantum numbers I introduced for describing doubly excited states of atoms are now well accepted  by the community. They are becoming textbook materials. I have also introduced classifications of triply excited states of atoms. The latter has not found its audience so far since experiments are yet to address such problems. I also introduced hyperspherical coordinates as universal tools for studying arbitrary three-body systems.  Since 2002, I have devoted fully to the topic of the interaction of atoms and molecules with intense laser fields, in order to make impact and become visible in this subfield.  I consider this goal has been reached.

The accomplishment is measured in terms of 306 published papers with 6216 citations as at the end of 2006. Contributions from graduate students, postdocs and collaborators  are to be recognized.