Photonic crystals (PCs) possess periodic modulation of the refractive index in dielectric materials which create a stop band in the photonic band structure.Colloidal photonic crystals (CPCs) are PCs using colloidal particles as building blocks.For many applications of CPCs, it is desirable to have a tunable stop band which is at the same time very broad.Colloidal photonic crystals with controlled gradients over sub-micrometer dimensions (GCPCs) were fabricated by a plasma etching method.