Measuring transmitted wavefronts for general optical systems in a broad bandwidth range

Abstract

Although laser interferometers have emerged as the main tool for the measurement of transmitted wavefronts, their application is greatly limited as they are typically designed for operations at specific wavelengths. In a previous study [Q. Zhang, H. Wang, P. Wu, Y. Fu, X. Li, Q. Wang, and S. Han, “Estimating transmitted wavefronts in a broad bandwidth based on Zernike coefficients,” J. Opt. 21(9), 095601 (2019)], we proposed a method for determining the wavefront transmitted by an optical system at any wavelength in a certain band. Although this method works well for most monochromatic systems where the image plane is at the focal point for the transmission wavelength, for general multi-color systems, it is more practical to measure the wavefront at the defocused image plane. Hence, in this paper, we have developed a complete method for determining transmitted wavefronts in a broad bandwidth at any defocused position, thereby enabling wavefront measurements for multi-color systems. We also conducted experiments to verify these assumptions, validating the method. The experimental setup has been improved so that it can handle multi-color systems, and a detailed experimental process is summarized. With this technique, application of broadband transmission wavefront measurement can be extended to most general optical systems, which is of great significance for the characterization of achromatic and apochromatic optical lenses.