Abstract

We investigate the anisotropy of the degenerate, instantaneous, third-order, bound-electronic nonlinearity χ⁽³⁾_ijkl in zincblende semiconductors by monitoring the rotated polarization component of the transmitted radiation in both single-and two-beam (pump–probe) experiments as a function of the crystal orientation and the incident pulse intensity. The measurements were conducted on a variety of semiconductors (GaAs, InP, CdTe, ZnSe, and GaP) by using an amplified, 1-ps Styryl 13 dye laser system operating at 950 nm. The results showed that the induced nonlinear polarization rotation of the transmitted signal due to the anisotropy σ of χ⁽³⁾, defined as σ = χ₁₁₁₁ − (χ₁₁₂₂ + χ₁₂₂₁ + χ₁₂₁₂), has the expected periodic dependence on crystal rotation for light propagating along the (001) and (110) crystallographic axes. For propagation along the (111) axis no polarization rotation was observed—a result that concurs with the fact that χ⁽³⁾ is isotropic in this direction. A time-delayed two-beam pump-probe measurement showed that the nonlinearity is instantaneous to within the 1-ps experimental resolution. In addition, the third-order of this nonlinear effect was confirmed in the pump-probe experiment by the dependence of the signal on the incident fluence. Determination of the components of the χ⁽³⁾ tensor by using this experimental technique will be discussed.

© 1992 Optical Society of America