Study on the influence factors of the mid-spatial-frequency wavefront PSD1 error for large-aperture mirrors

With the progress of high power laser system, the specifications of the large-aperture optics on the low-spatial-frequency wavefront, mid-spatial-frequency wavefront, high-spatial-frequency wavefront all meet stricter requirements. To the mid-spatial-frequency wavefront, it has been researched less than others. The influence factors of the mid-spatial-frequency wavefront PSD1 error for large-aperture mirrors are analyzed in this work. The results show that the influence factors of the mid-spatial-frequency wavefront is different with the low-spatial-frequency wavefront. PV error depends on the peak and vale of film surface，Grms error is affected by the big amplitude wave of film surface, and PSD1 error is mainly caused by the small frequency wave of film surface. So it is the key to controlling the PSD1 error for large-aperture mirrors that reducing small frequency wave of film surface.