Abstract

We report a new way of monitoring specific high-order susceptibilities, or high-order contributions to the nonlinear refraction index. It relies on angularly resolved emission in a phase-matched multiwave mixing configuration, to spatially discriminate a given-order contribution to the optical susceptibility. This technique, demonstrated here in near-resonance gas media, is generally applicable to a large class of nonlinear materials. High-order optical susceptibilities give direct access to the dielectric response of nonlinear media, and their knowledge is essential to such processes as phase conjugation or optical bistability and instabilities.

© 1984 Optical Society of America