Investigation of transient surface electric field induced by femtosecond laser irradiation of aluminum

Transient surface electric fields induced by femtosecond laser irradiation of an aluminum film were investigated directly by ultrashort electron pulses. At pump intensities of 2.9 ∼ 7.1 × 10 ^10 W cm ^−2 , the transient electric fields last at least one nanosecond with a maximum field strength of 3.2 ∼ 5.3 × 10 ^4 V m ^−1 at 120 μ m above the aluminum surface. The transient electric fields and the associated evolution of photoelectrons were explained by a ‘three-layer’ model. The potential influence of such fields on reflection ultrafast electron diffraction and time-resolved angle-resolved photoemission spectroscopy were evaluated.