A pre-ionized medium created by a capillary discharge results in more efficient use of laser energy in high-order harmonic generation (HHG) from ions. It extends the cutoff photon energy, and reduces the distortion of the laser pulse as it propagates down the waveguide. The observed enhancements result from a combination of reduced ionization energy loss and reduced ionization-induced defocusing of the driving laser as well as waveguiding of the driving laser pulse. The discharge plasma also provides a means to spectrally tune the harmonics by tailoring the initial level of ionization of the medium.
DOE DE-FG02-04ER15592 A001 through the Department of Energy Office of Basic Energy Sciences, "High Harmonic Generation in Discharge-Ionized Plasma Channels." Grant awarded to Colorado State University, with subcontract to University of Colorado.
National Science Foundation Cooperative Agreement No. EEC-0310717, NSF Engineering Research Center in Extreme Ultraviolet Science and Technology. Grant awarded to Colorado State University, with subcontract to University of Colorado.