Third- and fifth-order optical nonlinearities of norbixin

In this work, we investigated the nonlinear response of norbixin (C24H28O4) in acetone. The third- and fifth-order optical nonlinearities were measured using the conventional Z-scan technique, with 357 fs laser pulses at 1040 nm and low-repetition rate (1 kHz). It is shown that, at intensities lower than 99 GW/cm2, the nonlinear refraction process was determined by the only third-order process. However, at higher intensities, the third- and fifth-order refractive nonlinearities coexist with opposite signs: n2 = (4.43 +/- 0.44) x 10-16 cm2/W and n4 = (-4.65 +/- 0.46) x 10-27 cm4/W2. On the other hand, the open-aperture Z-scan measurements show an effective three-photon absorption (3PA) with (9.19 +/- 0.92) x 10-23 cm4/W2. The physical mechanisms of the observed nonlinearity are also discussed.