Aspheric Testing Based On Electronic Virtual Plane

Development of optical manufacturing, especially aspherical manufacturing, boosted the developing of space optics. Aspheric testing for large departures from reference wavefronts becomes the bottleneck of optical manufacturing. Off-axis TMA system presented in space cameras for large field, high resolution, long focal length challenges the manufacturing and testing for aspheric components .In this paper, we present the idea of virtual plate for aspheric testing based on moire phase-shifting technology, i.e. when testing steep aspheric wavefronts, interferometry directly used CCD camera for high resolution to obtain supervision with interferometry saved in the frame memory produces moire patterns. Finally, we cancel the noise (mainly in the high frequency) by means of low pass frequency .At last, we obtain digital four patterns by four step phase-shifting technology. Using modulo In to display phase, we got the fringe of the phase . In order to prove its feasibility , we contract the result of simulation with the result of the Zernike polynomial.The advantage of electronic moire phase-shifting technology is that sample directly avoids the system error and difficulty of calibration and aligning by optical compensators being applied.In electronic moire phase-shifting virtual plane technology, we began to research testing for the large departures from referent wavefronts and change the pattern of Offner Null testing in conventional aspheric testing, finally present the idea of electronic virtual plane. Meanwhile we discuss several types of aspheric non-null testing such as Sub-Nyquist, high-resolution CCD camera to sample directly.