A new method to measure low-order aberrations based on wavefront slope

Abstract

In this paper we discuss a new method to detect low-order aberration with large peak-valley value. This method also depends on wavefront slope measurements but only need measurements of 6 spots, which means that only 6 pieces of lens are used in detective process, and the mathematical algorithm involved in the calculation process is different from zonal or modal estimation used in Shack–Hartmann Wavefront Sensor. To evaluate the accuracy of this method we simulate this optical measurement process by using the Zemax simulation software and Matlab calculation software. Simulation results show that the reconstructed errors of Zernike aberration coefficients are higher for a larger peakvalley (PV) value of wavefront distortions. The maximal errors of aberration coefficients can be keep lower than 1% for aberrations with different combinations of defocus, astigmatism at 0° ,astigmatism at 45° and some high-order terms.. The new measurement method can be used to direct measure low-order aberrations for laser beam with large transverse area and do not need beam contracting system.