Picosecond cubic and quintic nonlinearity of lithium niobate at 532 nm
Résumé
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 cm/GW 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-carriers 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 support for previous experiments that indicate possible fifth-order processes in bulk samples and channel waveguides fabricated with LiNbO3.
Domaines
Optique [physics.optics]
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