Keith Adam Nelson

Developed methods for time-resolved, ultrafast optical measurements and control of collective and molecular behavior, providing insight into the dynamics of structural and chemical rearrangements and correlated electronic states. Discovered impulsive stimulated light scattering, enabling direct time-resolved observations of molecular vibrational oscillations, crystal lattice vibrations, and acoustic waves. This ubiquitous effect when ultrashort light pulses irradiate molecules or materials has been exploited by thousands of researchers worldwide. Experiments using femtosecond pulse shaping for coherent control, now also widely emulated. Developed spatiotemporal pulse shaping to enable control over terahertz waves in ionic crystals, providing basis for high-power terahertz pulse generation that spawned subfield of nonlinear terahertz spectroscopy and yielded the first terahertz field-induced phase transitions and fully coherent control and spectroscopy of multiexciton coherences as measured through the first multiple-quantum 2D optical spectroscopy. Recipient, the Ahmed Zewail Award in Ultrafast Science and Technology (American Chemical Society) and the Ellis R. Lippincott Award (Optical Society of America).