Third harmonic generation through coupled second-order nonlinear optical parametric processes in quasiperiodically domain-inverted Sr0.6Ba0.4Nb2O6 optical superlattices

A one-dimensional quasiperiodically domain-inverted optical superlattice has been designed and fabricated in a strontium barium niobate (Sr0.6Ba0.4Nb2O6) single-crystal plate. A third harmonic output generated through coupled second-order nonlinear parametric processes with a conversion efficiency of about 1.6% was obtained when both the second harmonic and the third harmonic were simultaneously quasiphase matched in the crystal.