Abstract

Optical methods of generating ultrafast electrical signals have been the focus of attention of a number of researchers in the last few years. Although the second-order nonlinear optical processes have long been known to generate low-frequency signals, the third-order processes were not seriously considered until recently. The obvious advantage of the third-order processes is that they exist in all types of materials, including centro-symmetric and amorphous, and do not require an external bias. The nature of third-order optical rectification requires the simultaneous presence of two mutually coherent fields at frequencies ω and 2ω, respectively:

© 1995 Optical Society of America