Controlling the intrinsic atomic phase in high-harmonic generation

Summary form only given.Recently, because of potential applications for coherent VUV and soft-x-ray sources in science and technology, the process of high-order harmonic generation (HHG) has received considerable attention. The dependence of the harmonic spectra on laser intensity, wavelength, polarization, and pulsewidth have all been studied experimentally and numerically. However, more detailed comparisons of models with experiment has proven to be difficult, primarily because of the lack of detailed and reliable experimental data. In this work, we provide a theoretical explanation for our experimental observation that the chirp of the excitation laser used to generate the harmonics dramatically changes the observed spectra of the high-harmonic output.