Influence of multifrequency vibration on the optical performance of diamond-turned optics and its elimination method

In this work, to reveal the underlying mechanism of the influence of multifrequency vibration on the optical performance of diamond-turned optics, a systematic simulation investigation is performed using Fourier modal method and fast Fourier transformation based on a well-established surface topography model. Both the simulation results and the experimental observations demonstrate that the center area is the most heavily influenced region on the machined surface, which is closely associated with the distribution of the surface roughness under multifrequency vibration. The vibration amplitude has a visible impact on the specular reflectivity, and with an increase in vibration amplitude, the specular reflectivity in the center area obviously decreases, while the specular reflectivity in remote areas basically remains invariant. To eliminate the negative effect in relation to the vibration, a two-step process technology is developed that includes a strict spindle balance and the optimization of process parameters, particularly the depth of cut and the spindle speed. The cutting experiments further validate the effectiveness of the proposed technology for elimination of the negative effect concerning multifrequency vibration.