The present technology provides an illustrative method for preparing fibers with desirable optical characteristics. The method includes providing a fiber that comprises a core layer and a cladding layer located around the core layer. The method further includes applying a nanostructure template to the cladding layer to form one or more photonic nanostructures having nanostructure scales and compressing the core layer to cause the core layer to bulge and form air gaps between the core layer and the one or more photonic nanostructures.