T-Jump

Our approach for generating a rapid, laser-induced T-jump is shown schematically above. An injection-seeded Nd:YAG laser pumps a pulsed dye laser (694 nm) which is differenced with the Nd:YAG fundamental (1064 nm) in a nonlinear LiNbO₃ crystal to produce the T-jump pump pulse at 2 µm (10 ns FWHM pulse width). The T-jump rapidly initiates either a folding reaction (from a cold-denatured state) or an unfolding reaction. We follow the temporal evolution of the protein structure with time-resolved infrared or fluorescence spectroscopy.