Picosecond processes studied using time-resolved spectroscopic techniques and a pulsed free electron laser

The Stanford Free Electron Laser (FEL) is a source of high peak-power, short-pulsed radiation tunable throughout the mid- and far-infrared. This light source is ideal for the study of nonlinear spectroscopic processes such as the characterization of the vibrational dynamics of molecules or the nonlinear optical response of engineered quantum well structures. We have developed a flexible experimental apparatus for conducting these nonlinear experiments. We present here three examples of published work done at the Stanford FEL Center which relied heavily on the unique and flexible characteristics of the Stanford FEL: pump-probe measurements of the SD stretch mode realization in amorphous As₂S₃, photon echo measurements of CO in three systems, and measurements of second harmonic generation in InGaAs/AlAs quantum wells. These examples are indicatives of the quality and variety of experiments performed at the Stanford FEL Center in collaboration with outside users.