Direct visualization of charge distributions during femtosecond laser ablation of a Si(100) surface

We directly observe the charge distributions and resulting electric fields present during the earliest stages of laser ablation of a Si (100) surface by using femtosecond electron pulses as a probe. We find the magnitude of the field to be 3.5 X 10(6) V/m just 3 ps after an excitation pulse of 5.6 J/cm(2). By fitting the data to a simple model, we determine that the excitation results in the rapid emission of 5.3 X 10(11) electrons/cm(2). These experiments provide new insights into the nature of the ablation process and the behavior of charged particles involved in it.