That is only the context i.e. prior art of their method. The novelty is in eliminating the etching and post-processing steps, by using a colored photoresist:

That is only the context i.e. prior art of their method. The novelty is in eliminating the etching and post-processing steps, by using a colored photoresist: > In this study, we present a simplified method for fabricating visible Fresnel zone plate (FZP) planar lenses, a type of diffractive optical element, using an i-line stepper and a special photoresist (color resist) that only necessitates coating, exposure, and development, eliminating the need for etching or other post-processing steps.