Fig. 1

a Flow chart of the liquid transfer method. For details, see Methods. b Schematic of NR array on Cr/Si substrate with periods Px, Py; average ring diameters Dx, Dy; ring widths (thicknesses) T, and height H. c–e Top-view SEM images of the three arrays, c NR1 with Dx = Dy = 200 nm and T = 49 nm, d NR2 with Dx = Dy = 200 nm and T = 83 nm, and e NR3 with Dx = Dy = 250 nm and T = 56 nm.