Optical second-harmonic generation in atomic vapors with focused beams

Processes leading to second-harmonic generation when a single polarized beam is focused into neutral or partially ionized atomic vapor are considered, including electric-field-induced third-order mixing, and quadrupole and magnetic dipole processes. Estimates of the relative strengths of these processes are given. In addition, the polarization properties given by the tensor susceptibilities are discussed in detail. © 1981 The American Physical Society.