We present a technique for single-beam measurement of the optical nonlinearity in GaAs for photon energies above the bandgap. We measured the real and the imaginary parts of the nonlinear refractive index of a bulk crystal by using the change in reflection of dye laser pulses (10 ns, 538 nm). The values obtained, <i>n</i><sub>2</sub> = (7.8 ∓ 0.6) × 10<sup>−8</sup> cm<sup>2</sup>/W and κ<sub>2</sub> = (−2.8 ∓ 0.7) × 10<sup>−8</sup> cm<sup>2</sup>/W, are discussed.
© 2000 Optical Society of America
Marcelo Martinelli, Laércio Gomes, and Ricardo J. Horowicz, "Measurement of Refractive Nonlinearities in GaAs Above Bandgap Energy," Appl. Opt. 39, 6193-6196 (2000)