Ronchigram analysis based on effective wavelength techniques and wavefront slope

In this paper, some concepts and results associated with the interferometric concept of effective wavelength have been applied for the evaluation of optical surfaces. This testing technique measures the wavefront slope instead of the contour of the wavefront, like in the conventional interferometry. Therefore in this paper we present two methods of analysis of optical surfaces with the Ronchi test. First, we described a procedure to evaluate surfaces employing the effective wavelength in the Ronchi test [1]. Our results were computationally processed in order to reconstruct the wavefront of a particular mirror by means of the effective wavelength. A second proposal technique of analysis is based on the change of the traditional analysis of a ronchigram to a method by a proper scaling of the shearing interferogram, via the equivalent wavelength. The effective wavelength and equivalent wavelength are distinct concepts and are independent of the wavelengths used in the image registering process. Comparisons of the Zernike Polynomials for each wavefront with a reference wavefront show, the differences between both methods. Finally, we discuss some advantages and disadvantages of each of the proposed analysis and mention the principal factors to improve our results.