Office: JILA A703
Research Interests:
Ultrafast laser technology, ultrafast dynamics in Molecular and materials systems, and development of tabletop coherent x-ray sources.
My primary interest is in developing-- and making use of-- new tabletop "x-ray laser" light sources. 20 years ago, the process of "high order harmonic generation" (HHG) was discovered, where an intense short pulse laser focused into a gas at high intensity was shown to produce light at very high-order harmonics of the driving laser . By implementing this technique using new laser technologies we developed, it became possible to drive this process to an extreme, generating x-ray light that still retains the coherence of the driving laser. However, to implement this tehcnique in a useful way requires an understanding of nonlinear optics in a very different regime than has been studied in the past, necessitating a new way of thinking about phase matching of nonlienar optical processes. During the past decade, we have developed a variety of techniques that allow us to phase-match and quasi-phase match the HHG process. The result is a useful tabletop coherent x-ray source that has applications in in wide variety of scinetific investigations, as well as for technological applications such as nanoscale imaging. The very short-pulse (femtosecond-to-attosecond) nature of these sources makes them useful for studies of ultrafast dynamics, and we have used this source for studies of x-ray induced molecular dissociation, for studies of heat transport on the nanoscale, and for studies of magnetism dynamics (among other things).
Selected Publications:
For a list of Professor Kapteyn’s latest publications visit https://jila.colorado.edu/kmgroup/publications/scientific/year