Research of precision interference locating method for a partial null compensator at aspheric testing

摘要

Based on the difference between theoretical with real interferogram images the figure of original aspheric surface can be obtained using an algorithm of Reverse iterate Optimization Reconstruction (ROR) calculating technique. Because the procedure of ray tracing path needed an accurate geometry of optical structure size so the aspheric and compensator L_C must be located in the optical path. To avoid the compensator L-C resulted in bigger spherical aberration a smart located method is proposed in this paper. Before measurement an aplanatic lens consists of compensator L_C and another removable lens L_M that the last surface is a standard one. So Fiezau interference is formed by the standard one with reflected ray from the vertex of aspheric that the aspheric surface detected can be accurately located. At testing the lenses L_M will be removed and the aspheric is moved to an adapted position. The experiments show the displacement locating accuracy is an amount of micron. The RMS for aspheric testing of ROR calculating technique is better than 1/200 wavelength.