Inspection of aspherical lenses by wavefront analysis

A new approach for quantifying the optical aberrations of aspherical lenses is presented. A measurement setup is developed which measures the local wavefront slopes using a motorized scanning system. The simulation results of the setup are presented in order to validate the potential of the measurement principle. Experimental results by the measurement of a commercial aspherical lens verify the theoretical investigations. Dynamic range of the measurable Zernike coefficients and Peak to Valley (P-V) wavefronts are quantified. Focal length of the aspheric lens under test is calculated from the Zernike coefficients which are determined by performing a nonlinear regression analysis for the measured slopes and the partial derivatives of the wavefront. Furthermore, 3rd order spherical aberration term of the wavefront is analyzed dependent on different wavelengths.