Absolute measurement method of transmission wavefront distortion of spherical lens

The transmission wavefront distortion of spherical lens is an important factor influcing the light beam quality for high power laser drivers.The precision of spherical lens wavefront measured by Fizeau interferometer is limited by the precision of standard spherical lens and the rear flat. However, the existing absolute testing method applies to reflecting element only. To remove the error of standard spherical lens and the rear flat and improve the test precision of spherical lens transmission wavefront, an absolute method,three positionshifting method, was proposed. The principle of this method was introduced in detail, the simulation and the verified experiment were performed. The simulation results show that the simulation error is 10 nm~13 nm,meeting the theorotical requirement of highprecision measurement; Experiment results show that in spherical lens wavefront measurement, three positionshifting method can effectively reduce the influence of standard spherical lens and rear flat on the measurement results. This method has a good guidance for processing and alignment of spherical lens.