• Advanced Photonics Nexus
  • Vol. 3, Issue 6, 066009 (2024)
Yuan Li1, Xiuquan Zhang2, Lutong Cai1,*, and Lin Zhang1,3,*
Author Affiliations
  • 1Tianjin University, School of Precision Instruments and Opto-Electronics Engineering, State Key Laboratory of Precision Measuring Technology and Instruments, Key Laboratory of Opto-Electronic Information Technology of Ministry of Education, Tianjin Key Laboratory of Integrated Opto-Electronics Technologies and Devices, Tianjin, China
  • 2Shandong University, Ministry of Education, Key Laboratory of Laser and Infrared System, Qingdao, China
  • 3Peng Cheng Laboratory, Shenzhen, China
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    DOI: 10.1117/1.APN.3.6.066009 Cite this Article Set citation alerts
    Yuan Li, Xiuquan Zhang, Lutong Cai, Lin Zhang, "Highly efficient second-harmonic generation in a double-layer thin-film lithium niobate waveguide," Adv. Photon. Nexus 3, 066009 (2024) Copy Citation Text show less

    Abstract

    Thin-film lithium niobate (LN) has emerged as an ideal platform for efficient nonlinear wave-mixing processes due to its strong quadratic nonlinearity and high optical confinement. We demonstrate unprecedentedly efficient second-harmonic generation (SHG) in a double-layer thin-film LN waveguide. The modal overlap between fundamental and second-harmonic waves is significantly enhanced by the polarization-reversed double layers, leading to a normalized conversion efficiency higher than 10,000 % W - 1 cm - 2 in theory. Under the low- and high-power pumping conditions, the measured normalized and absolute conversion efficiencies are 9600 % W - 1 cm - 2 and 85 % , respectively, substantially higher than state-of-the-art values among the reported SHGs in thin-film LN waveguides. Our results hold great promise for the development of efficient and scalable nonlinear photonic devices, with applications including metrology and quantum information processing.
    k2ω=2kω,

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    ASHy=αSH2ASHiκSHAf2exp[iΔky],

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    Afy=αf2AfiκfASHAf*exp[iΔky],

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    κSH=d33ωSHπcnSHEf2(x,z)ESH(x,z)dxdzESH2(x,z)dxdz,

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    κf=2d33ωfπcnfEf2(x,z)ESH(x,z)dxdzEf2(x,z)dxdz,

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    Δk=kSH2kf.

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    P2ω=ηnormL2Pω2g(L),

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    ηnorm=8d332ε0cnSHnf2λSH2Seffsinc2(ΔkL2)

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    Seff=[Ef2(x,z)dxdz]2ESH2(x,z)dxdz[Ef2(x,z)ESH(x,z)dxdz]2,

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    g(L)=e2αfL(eΔαL+1)24cos2(ΔkL2)eΔαLΔα2+Δk2,

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    Δα=αfαSH2.

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    Γ=LNd33(x,z)Ez,ω2(x,z)Ez,2ω(x,z)dxdz.

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    dne,FWdT=2.6+19.8×103T,

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    dne,SHdT=2.6+22.4×103T.

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    Yuan Li, Xiuquan Zhang, Lutong Cai, Lin Zhang, "Highly efficient second-harmonic generation in a double-layer thin-film lithium niobate waveguide," Adv. Photon. Nexus 3, 066009 (2024)
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