Scanning tunneling microscopy using dynamic laser heating

A hydrogen passivated Si(100)-2×1 surface is studied using ultrafast laser excitation with a novel total internal reflection geometry. The incoherent tip and sample heating dynamics are studied, and it is shown that as long as the STM feedback is faster than the heating and cooling processes, atomic scale imaging can be achieved, even in the presence of significant tip and sample expansion and contraction. This opens the door for studies of surface processes on the ultrafast timescale.