The azimuthal dependence of third-order and cascaded second-order nonlinear coupling was used to measure the relative contributions of each to direct third-harmonic generation in <i>β</i>-barium borate. This permitted the measurement of the values of tensor elements χ<sup>(3)</sup><sub>10</sub> , χ<sup>(3)</sup><sub>11</sub> , and χ<sup>(3)</sup><sub>16</sub> relative to the known χ<sup>(2)</sup><sub><i>ij</i></sub> . Finally, conversion efficiencies to 3⍵ of up to 6% were achieved with a femtosecond chirped-pulse amplification laser with 200 GW/cm<sup>2</sup> in collimated beams.
© 1999 Optical Society of America
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.4720) Nonlinear optics : Optical nonlinearities of condensed matter
(190.7220) Nonlinear optics : Upconversion
(320.2250) Ultrafast optics : Femtosecond phenomena
(320.7110) Ultrafast optics : Ultrafast nonlinear optics
P. S. Banks, M. D. Feit, and M. D. Perry, "High-intensity third-harmonic generation in beta barium borate through second-order and third-order susceptibilities," Opt. Lett. 24, 4-6 (1999)