Sidewall Kink Elimination of Slanted Gratings Utilizing a Twice-Etching Method

The slanted grating is crucial to cutting -edge disciplines like spectroscopy, augmented reality (AR), virtual reality (VR), etc. The kink of the slanted grating sidewall will affect the diffraction efficiency of the optical waveguide couplers utilized in AR devices. In the fabrication of slanted gratings in reactive ion beam etching (RIBE), a kinky sidewall is difficult to avoid. A twice-etching method is proposed to resolve this issue. Through the combination of two processes, a better slanted grating morphology without kinky sidewall is achieved. This work has good guiding significance for the fabrication of slanted gratings.