Abstract

Harmonic generation from ultrafast, ultra-intense lasers has proven to be an excellent source of coherent radiation in the soft x-ray regime.[1,2] Our recent work[3,4] has shown that very short driving pulses can generate broad bandwidth harmonic peaks, which are tunable, and with a cut-off at wavelengths substantially shorter than harmonics produced with longer duration pulses. In this work, we show how shaping the amplitude and phase of our laser pulses, to ensure faster risetimes and and optimal shapes, can enhance the efficiency of harmonic generation, as well as extend the plateau to even shorter wavelengths. We employ novel shaping techniques, using birefringent filters, and spectral shaping elements, to produce these effects.

© 1997 Optical Society of America