Reflectance characteristics of nanopillars with varying widths. (a) Experimental setup for the reflectance measurement. BP: beam splitter, L: lens. CCD images of (b) the substrate and (c) the nanopillars illuminated by wideband light source, respectively. (d) Numerically evaluated reflectance of the nanopillars. (e) Experiment results of the reflectance for the nanopillars, the lowest reflectance of the pump beam is ~7.53% when w = 215 nm around the wavelength of 780 nm.