Modal analysis of rotating mirror for ultra-high-speed cameras

We theoretically and numerically investigated the modal properties of three different kinds of cross-section rotating mirrors. At the same facet size, the fundamental frequency of equilateral-triangle cross-section rotating mirror (ET-RM) was 8725.4 Hz, which was 1.81 times and 4.60 times higher than that of equilateral-square and equilateral-hexagonal rotating mirrors. The displacement response curves of the three kinds rotating mirrors show that the amplitude of the first peak is further larger than the second one. The first bending modal of rotating mirror is the main reason of the damage for rotating mirrors. The maximum working speed of ET-RM with face size of 17.32 mm × 36 mm is 44,400 rpm. That of the other two kinds of rotating mirror are 37,800 rpm and 27,000 rpm respectively. The equilateral-triangle cross-section as an ideal structure of rotating mirror for ultra-high-speed cameras based on the dynamic properties.