Wavefront measurement for long focal large aperture lens based on talbot effect of ronchi grating

Abstract

We propose a wavefront measurement method based on Talbot effect. It is well known that the wavefront of large aperture long focal lens is difficult to be measured. Here a new method for wavefront measurement of large aperture long focal lens is presented, which is accomplished by fitting the slope of sub-wavefront in the whole aperture while the sub-wavefront slope is got by calculating the shifted moiré fringe numbers formed by Talbot effect of Ronchi grating in different position of the aperture. The formula of calculating the angle of subwavefront slope from the shifted moiré fringe numbers is derived. Error analysis demonstrates that this method can be applied to the wavefront testing with high accuracy. © 2006 IOP Publishing Ltd.