A micro structure for sensing a substance using light scattering includes a substrate, a first layer on the substrate, wherein the first layer comprises a metallic material, a second layer over the first layer, and a mask layer over the second layer. A plurality of nano holes are formed through the mask layer and the second layer, wherein the plurality of holes are defined in part by internal surfaces on the second layer and the mask layer. Two or more structure layers are formed on the mask layer and the internal surfaces in the plurality of holes. The two or more structure layers comprise different material compositions.