Abstract

The use of quasi-phase-matching (QPM) technique to compensate the phase velocity difference in interacting optical waves has greatly revived the field of nonlinear optics. A plethora of research activity has benefited from the availability of periodically poled lithium niobate (PPLN) and lithium tantalate (PPLT). These structures are characterized by a periodical sign reversal in the second-order nonlinear susceptibility χ⁽²⁾ every coherent length, l_c = λ_ω/4(n_2ω-n_ω), to compensate the destructive interference caused by the material’s dispersion in the refractive index, n. Great challenge, however, remains in manipulating the coercive and fringing field to achieve a high fidelity of pattern transfer in making fine QPM structure to raise up the conversion efficiency.¹ The use of quasi-phase-matching (QPM) technique to compensate the phase velocity difference in interacting optical waves has greatly revived the field of nonlinear optics. A plethora of research activity has benefited from the availability of periodically poled lithium niobate (PPLN) and lithium tantalate (PPLT). These structures are characterized by a periodical sign reversal in the second-order nonlinear susceptibility χ⁽²⁾ every coherent length, l_c = λ_ω/4(n_2ω-n_ω), to compensate the destructive interference caused by the material’s dispersion in the refractive index, n. Great challenge, however, remains in manipulating the coercive and fringing field to achieve a high fidelity of pattern transfer in making fine QPM structure to raise up the conversion efficiency.¹

© 2002 Optical Society of America