Controlling the phase evolution of few-cycle light pulses

Using a coherent nonlinear optical technique, slipping of the carrier throu gh the envelope of 6-fs light wave packets emitted from a mode-locked-oscil lator/pulse-compressor system has been measured, permitting the generation of intense, few-cycle light with precisely reproducible electric and magnet ic fields. These pulses open the way to controlling the evolution of strong -field interactions on the time scale of the light oscillation cycle and ar e indispensable to reproducible attosecond x-ray pulse generation.