Abstract

The cascading of second order nonlinearities (χ⁽²⁾: χ⁽²⁾ to induce a nonlinear phase distortion on the input beam has recently received considerable attention[1,2] We estimate that materials with large second order nonlinearities (≃10² pm/V) will give rise to effective nonlinear refractive indices, ${\text{n}}_2^{\text{eff}}$, of 10^–12 to 10^–10 esu. These nonlinearities are truly nonresonant and can be in a lossless spectral region (i.e. loss determined by impurities and defects). An important difference between this nonlinearity and a true χ⁽³⁾ nonlinearity is that the sign is readily changed by, for example, changing the phase matching condition.

© 1992 Optical Society of America