Optimizing the fabrication process of a high-efficiency blazed grating through diamond scribing and molding

This paper presents the experimental investigation of an optimal hot embossing process to prevent the nanoscale thermal deformation of microstructures replicated from the electroless Ni mold fabricated by the diamond tool-interfered scribing method. A polymer-based PMMA was replicated from the mold with the blazed profile: period 2.0 μm and depth 0.2 μm. The molding conditions, the applying pressure (P_m), molding temperature (T_m) and demolding temperature (T_d) were chosen as experiment parameters. In terms of the quality of surface smoothness, profile, sharp edge, surface roughness and optical performance of the replica, the conditions, P_m = 0.9 MPa, T_m = 150 °C and T _d = 20 °C, showed a best results. From optical testing, diffraction efficiency of the replica was measured, 87.6%, and the replica molded in other conditions showed a noticeable efficiency drop due to the molding error.