Surface nonlinear optics: a historical overview

The availability of widely tunable dye lasers and optical parametric oscillators permit the detection of surface specific electronic and vibrational states. Polarization dependent studies yield information about the orientation of molecular monolayers and surface specific bonds. The use of picosecond and femtosecond pulse-probe techniques permits time-resolved studies of surface phase transformations, desorption, and melting. A few examples from the rapidly growing literature are selected to illustrate this historical evolution.