Phase and polarization control of the harmonic emission: Towards attosecond pulses

In the first section we demonstrate the generation of four phase-locked harmonic pulses separated in time using frequency-domain interferometry. The spectra present a high sensitivity to a change of the relative phase on an attosecond time scale. The spectral resolution and the control of this relative phase could be used to perform high resolution measurements. In the second section we demonstrate temporal gating technique to isolate attosecond pulses. Recent results of such a gating showing a spectral broadening are reported. We show that this enlargement can unambiguously be attributed to a temporal confinement by a factor 2 of the harmonic emission