Evaluation of the surface topography quality of large-area diamonds by image processing and mathematical modeling

Diamond with ultra-smooth and flat surface plays a crucial role in the various fields of nonlinear optics, NV center, waveguide, and so on, due to its remarkable physical properties. Consequently, the fast and efficient polishing and evaluating of diamond surfaces are indispensable to obtain high-quality smooth and flat diamond surfaces. As one of the most widespread techniques, atomic force microscope (AFM) and optical profilometry (OP) are enslaved to their small measurement regions and high time consuming, especially in the case of high-resolution measurement of large area diamond surfaces. Therefore, a novel approach to evaluate the polished diamond surface with high-efficiency and accuracy is desperately required. In this works, we propose a novel approach, surface topography quality (STQ) mathematical model, to achieve fast and large area evaluation to the polished diamond surface. Specifically, by combining currently popular image processing with mathematical statistics, STQ mathematical model generates a concept called surface topography quality rate (STQR) to quantitatively evaluate the surface quality of diamond. The results from large-area scanning electron microscope images before and after ion beam polishing demonstrates its reliability and preponderant advantage in dealing with large area surface compared to that of the conventional use of atomic force microscope. The mathematical model provides a unique and reliable approach to comprehensively and objectively evaluate diamond surface, which may promote the advancement of high-performance diamond-based devices.(c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement