Coherent control of atoms and molecules, for applications in nonlinear optics

The use of temporally-shaped ultrafast light pulses to control the dynamic evolution of atomic and molecular systems is a topic that has had a number of recent successes. This work applies concepts of nonlinear and ultrafast optics to possible practical use for goals such as optical "catalysis" of chemical reactions. However, coherent control concepts also have consequences for nonlinear optics itself, in making possible new nonlinear techniques. We have recently demonstrated two new techniques that make it possible to generate ultrashort-pulse light with unprecedented capabilties. In the first, we generate high-harmonic radiation using shaped light pulses. This work takes advantage of the attosecond time-scale dynamics of the high-harmonic process to enhance the temporal coherence of the light source. In the second technique, we use coherently spinning molecules to phase modulate a single ultrafast pulse in a way that makes it possible to subsequently compress the pulse using positive dispersion from material propagation. This technique promises to make possible new light sources in the deep-UV to EUV regions of the spectrum.