Research Interests

The interaction of light and matter is of fundamental interest to the fields of both physics and chemistry. Advances in laser technology continually push the interaction to higher energies, reaching unexplored intensities in which new science is emerging. Very intense laser pulses remove electrons from atoms through the quantum mechanical process of tunneling. This "strong-field ionization" is the birthing process for electrons involved in many important physical phenomena including high-harmonic generation, orbital tomography, attosecond pulse generation, and novel forms of lithography. Gaining a better understanding of electron interaction effects and their involvement in strong-field ionization has important consequences for further developing techniques of using intense laser pulses to measure the electronic properties of molecules, clusters, and solid state materials.

I am interested in learning how quickly electrons can respond to ultrashort (femtosecond or even attosecond) laser pulses. Using gas-phase optics, we generate a table-top x-ray laser that has the ultimate temporal resolution characterized in the attosecond timescale. An attosecond is defined as a billionth of a billionth of a second, and is the timescale of electron motion. This laser pulse is sensitive to not only the element, but also the oxidation state, electronic spin state, and charge state of the atoms, while also having the time resolution to monitor the changes in real time. This unparalleled view of electron motion allows us to finally resolve electron dynamics and gain a fine understanding of how electrons transfer between atoms and across molecules. By monitoring the first instances of electron motion, we explore how various pathways influence the outcome of a chemical reaction or photoexcitation.