Time-resolved spectroscopy of superconductors using synchrotron infrared pulses (abstract)

Infrared synchrotron radiation is a high brightness, pulsed source that enables a variety of novel spectroscopic techniques. One of these is time-resolved, broadband spectroscopy for probing dynamical processes. At the National Synchrotron Light Source (Brookhaven) we have implemented a synchronized laser system for performing pump–probe spectroscopy of superconductors and other materials. In the case of superconductors, we use laser pulses to break Cooper pairs, producing an excess population of quasiparticles. The relaxation (recombination) of this population is then probed with synchrotron infrared pulses, and analyzed in terms of the intrinsic relaxation times for excited quasiparticles and phonons. This presentation will describe the time-resolved technique and results for various metallic and oxide superconductors.