%0 Journal Article %J Nature Communications %D 2017 %T Metasurface-assisted phase-matching-free second harmonic generation in lithium niobate waveguides %A Wang, Cheng %A Zhaoyi Li %A Myoung-Hwan Kim %A Xiao Xiong %A Xi-Feng Ren %A Guang-Can Guo %A Nanfang Yu %A LonĨar, Marko %B Nature Communications %V 8 %G eng %N 2098