Coloring nanowires without colorants

Something is of a particular hue usually because it is intrinsically that color, like the leaves of green plants. But equally likely the color of an object, small like a soap bubble or a bird feather, or immense like the firmament, appear to be of a particular color because it simply reflects (or to be precise scatters) that wavelength of light. We use the former pigment colors when we paint …