The Generation of Laser Difference Frequencies Using the Scanning Tunneling Microscope

Infrared laser radiation and radio-frequency signals were coupled into the tunneling junction of a scanning tunneling microscope and the difference frequencies and their harmonics generated in the nonlinear junction were studied as a function of the tunneling parameters. The importance of the results for the difference-frequency mixing in metal-insulator-metal diodes and for the scanning tunneling microscope is discussed.