Determining the absolute phase and intensity of a two-color laser field
POSTER
Abstract
The left-right asymmetry of electron emission from single atoms by intense few-cycle 800 nm pulses is well known and forms the basis of the stereo-phasemeter method$^{1}$ of measuring the carrier-envelope phase of short pulses. Here we report experiments which demonstrate a similar asymmetry caused by the superposition of two colors (800 and 400nm) forming many-cycle pulses. We obtain Xe spectra as a function of the phase between the two colors. The spectra exhibit a pronounced left-right asymmetry as a function of phase in both the ``direct'' and the ``plateau'' regions of electron energy. Recently established quantitative rescattering theory (QRS) allows us to analyze momentum images of the rescattering (plateau) high-energy electrons. Using QRS theory we can determine accurately the laser peak intensity and the absolute phase of the two-color electric field. Our results also agree with semi-classical calculations. $^{1}$G. G. Paulus et al., PRL \textbf{91}, 253004 (2003).