Periodically Poled Nonlinear Photonic Crystal KTa_(0.51)Nb_(0.49)O_3 Combining Wide Transparent Range and Large Quadratic Coefficient

摘要

Since the first proposal of quasi-phase-matching (QPM) in 1962, finding newnonlinear photonic crystals has been an attractive topic in nonlinear opticsfields. However, combining high conversion efficiency and wide operationrange concurrently into one single crystal remains a great challenge. Herein, aperiodically poled KTa_(0.51)Nb_(0.49)O_3 (PPKTN) is fabricated as a one-dimensionalnonlinear photonic crystal for the first time, to the authors’ best knowledge.Benefitting from the large quadratic nonlinear coefficient, the QPM secondharmonic generation (SHG) at 1030 nm is realized with a high conversionefficiency of up to 39. More importantly, KTN crystal possesses wider midinfraredspectral transparency (0.4–8.0 μm) than commercialized LiNbO_3 andKTiOPO_4. A 5 μm SHG is first achieved with a conversion efficiency of 6.3,indicating that it is a promising candidate for broadband mid-infrared parametricconversion. This work promotes PPKTN as a new nonlinear photonicplatform to achieve highly efficient optical waveguide, holography, informationstorage, and all-optical chips.