Abstract

By combining ultrashort laser pulse techniques with scanning tunneling microscopy (STM), we have developed an instrument that obtains simultaneous 2-ps tune resolution and 50-Å spatial resolution. This is a 9-orders-of-magnitude improvement over the time resolution previously attainable with STM. We have used this instrument to measure the response of the tunneling gap to excitation by a subpicosecond electrical pulse. Our technique is not limited to STM; it can be implemented in a variety of scanning-probe microscopies, allowing the observation of ultrafast dynamics on the atomic scale.

© 1994 Optical Society of America