Abstract

Optical IR-visible sum-frequency generation (SFG) is a technique similar to surface second- harmonic generation (SHG) in that it is forbidden (in the dipole approximation) in spatial regions possessing inversion symmetry. For systems consisting of an interface bound by centro-symmetric media, the nonlinear response has been shown¹ to be dominated by the molecular species in the interfacial region. This specifity makes nonlinear optical techniques particularly attractive for studies of molecular adsorption and interactions at liquid/solid interfacial systems.

© 1991 Optical Society of America