Ultrafast dynamics and carrier-envelope phase sensitivity of multiphoton photoemission from metal surfaces

Subcycle dynamics of multiphoton-induced photoelectron emission from metal surfaces is analysed using a simple phenomenological model to assess optimum conditions for direct carrier-envelope phase measurement. To gain further insight femtosecond time-resolved measurements were carried out on a polycrystalline gold surface with ultrashort laser pulses to explain the recently found, unexpectedly low carrier-envelope phase dependence of the photoemission process in this particular case. In the higher-order interferometric autocorrelation distribution additional short side wings appeared suggesting that ultrafast dynamics of hot electrons reduce the carrier-envelope phase dependence of the photoemission electron yield produced by few-cycle laser pulses. Other metals can be investigated with this simple and fast method to pave the way towards the construction of a solid-state-based, direct carrier-envelope phase detector.