Atomic resolution in photon emission induced by a scanning tunneling microscope

A low temperature ultrahigh vacuum scanning tunneling microscope (STM) is used to excite photon emission from Au(110) surfaces. In the detected photon intensity the (1x2) reconstruction of the gold surface is clearly resolved. This first observation of atomic resolution in STM-induced photon emission is interpreted in terms of local variations of the electromagnetic interaction of tip and sample occurring at constant tunneling current. Similar effects are expected to affect other scanning probe methods, in particular those involving photons.