Spectral filtering of high-order harmonics via optics-free focusing

Generation of high-brightness high-order harmonics

Optimization of high-order harmonic generation has been studied with a 30 fs laser at an intensity of < 2×1014 W/cm in a quasi-static gas cell filled with argon and Neon. The effect of propagation length and gas density on the conversion efficiency and spatial quality of high-order harmonics are investigated comprehensively. As a result of phase-matched propagation, both the spatial quality and...

Spatial Mode Control of High-Order Harmonics.

Generation of High Order Harmonics from H2+ Molecule Ion by Using Homogenous and Inhomogeneous Laser Fields

We solved one dimensional Schrodinger equation in a H2+ molecular environment by using 3 femtosecond homogeneous and nonhomogeneous laser fields. In homogeneous case, we found out that larger inter nuclear distances result in earlier ionization and also more instability in the wave packet. We deducted that the more the instability is, the more modulated the power spectrum will be. So, by choosi...

Ramsey-type spectroscopy with high-order harmonics.

We present an experiment where Ramsey-type spectroscopy is applied to autoionizing states of krypton by using the ninth harmonic (88 nm) of a femtosecond Ti:sapphire laser. The ionization process, detected by an electron-energy spectrometer, shows the characteristic quantum interference pattern. The behavior of the fringe contrast compares favorably with a simple essential-state model, whose pa...

Temporal and spectral studies of high-order harmonics generated by polarization-modulated infrared fields