Improved master-replica separation process for fabrication of a blazed concave grating by using a combination-type convex grating.

An imprinting process that enables fabrication of blazed concave gratings with small radius and large curvature is presented. In this process, a combination-type convex grating substrate is used as a master to replace the single part used in the traditional process. The two parts of the combined convex grating are independently separated from the resist layer. In this manner, the concave blazed grating pattern in the resist can maintain maximum consistency with that on the combined convex grating. Experiments are conducted to demonstrate the feasibility of a two-step fabrication technology.