Picosecond cubic and quintic nonlinearity of lithium niobate at 532 nm

• Published in: Journal of applied physics 2017-08, Vol.122 (8)
• Main Authors: Wang, Hongzhen, Boudebs, Georges, de Araújo, Cid B.
• Format: Article
• Language: English
• Subjects: Absorptivity; Applied physics; Conduction bands; Lithium niobates; Neodymium lasers; Nonlinear response; Nonlinearity; Optics; Photon absorption; Physics; Refractivity; Semiconductor lasers; Waveguides; YAG lasers
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4987028

The nonlinear (NL) optical response of bulk lithium niobate (LiNbO3) was investigated at 532 nm using the second harmonic of a Nd:YAG laser delivering pulses of 12 ps. The experiments were performed using the D4σ method combined with the conventional Z-scan technique. Two- and three-photon absorption coefficients equal to 0.27   c m / G W and 2.5 × 10 − 26 m3/W2, respectively, were determined. The NL absorption processes were due to transitions from the valence to the conduction band and to free-carrier absorption. The third- and fifth-order NL refractive indices were n 2 = ( 2.5 ± 0.6 ) × 10 − 19 m2/W and n 4 < 5.5 × 10 − 36   m 4 / W 2 . The present results give the support for previous experiments that indicate possible fifth-order processes in bulk samples and channel waveguides fabricated with LiNbO3.