9724436 Sherwin A tunable, far-infrared, picosecond source will be developed based on the free electron laser (FEL) facility at the University of California-Santa Barbara (UCSB). The pulsed, far- infrared source will support research in several areas of condensed matter physics, mostly nonlinear dynamics of semiconductor heterostructures and of superconductors at terahertz frequencies. %%% The light source to be developed will fulfill a current need for a short-pulse, far-infrared user facility in the country. The new FEL capability has potential applications in other areas besides condensed matter physics, such as molecular spectroscopy, molecular chemistry, and biophysics. ***