Multiwavelength lateral-shearing spherical interferometry for a large-aperture dichroic mirror

Large-aperture dichroic mirrors play an important role in various high-power laser systems and have been proposed for multiwavelength wavefront measurements. In this study, we first developed the theory of multiwavelength lateral-shearing spherical interferometry to achieve signal separation under coaxial conditions. Subsequently, an experiment on wavefront sensing from one interferogram was successfully performed on a dichroic mirror with a diameter of 350 mm. The results are consistent with those of the Zygo interferometer, indicating the proposed method’s potential applications in high-order harmonic detection, multiwavelength interferometric imaging, and laser plasma diagnosis.