Fig.6

SHG emission from noncentrosymmetric nanostructures. The split-ring (a, f) chiral G-shaped (b), L-shaped (c), T-shaped (d) and single Au-Al heterodimer (e) nanostructures were used to enhance the SHG emissions. Reprinted with permission from Advanced Materials 2019, 31, e1806479 (a), Nano Letters 2009, 9, 3945–3948 (b), Nano Letters 2012, 12, 673–677 (c), Nano Letters 2007, 7, 1251–1255 (d), Nanoscale 2019, 11, 23,475–23,481 (e). Copyright 2019 Wiley–VCH GmbH; 2009, 2012, 2007 American Chemical Society; 2019 Royal Society of Chemistry