Two methods of analysis of wavefronts. Some examples and applications.

Two methods of analysis of wavefronts. Some examples of applications. Antonio Marzoa1, Santiago Vallmitjana1, Salvador Bosch1 and Eva Acosta2 1Departament de Física Aplicada i Òptica, Facultat de Física, Universidad de Barcelona, 08028 Barcelona, Spain 2Departamento de Física Aplicada, Facultade de Óptica e Optometría (Campus Vida), Universidade de Santiago de Compostela, Santiago de Compostela, Spain Theoretical background: Optical Systems and the PSF Generalized (black box) optical system. An on-going study: Optical quality assessment and determination of geometrical parameters of antique optical instruments. Summary Two experimental techniques for analyze wavefronts are presented. On one hand a non-contact technique for analyzing the image quality of antique optical instruments is proposed. We use a wavefront sensor, in particular a Shack–Hartmann device placed at the exit of the instrument in combination with a suitable illumination is presented. So, using the experimental parameters provided by the Shack-Hartmann wavefront analyzer (Zernike polynomial coefficients) and our own software we are able to calculate the PSF of the instrument that we are studying, and then calculate the convolution within the PSF and the function that describes a paraxial image. On the other hand we present a technique based on the use of a Point Diffaraction Interferometre (PDI). As examples of applications we have applied this interferometric technique for the measurement of local curvatures and caustics of noisy wavefronts in the particular case of crystalline lenses of fish eyes. This analysis allows us to obtain much information about the imaging of highly aberrated or noisy optical elements such as crystalline lenses of fishes. Diagram of the experimental and computing procedure for obtaining the PSF of an old optical instrument with Shack- Hartmann device’s experimental results, and the method for obtaining a simulated image as it’d seen through the antique optical instrument. This work was supported by the Spanish Ministry of Economy and Competivity, project FIS2012-38244. Computational implementation Experimental Measurements Experimental set-up for obtaining the Zernike polynomial coefficients of the aberrated wavefront by an antique optical instrument (terrestrial telescope) using a Shack-Hartmann wavefront sensor. We’re going to use this method and configuration in the study of antique microscope objectives. LS C O SH Experimental set-up for obtaining the focal distance of telescope’s objectives with a very big aperture. From left to right: Light source (LS), Collimator (C), Objective (O) and Shack- Hartmann device (SH). Using this configuration we can determinate the focal length of the objective that we are studying and the refractive index of each lens that compose the objective. Point diffraction interferometer applied on the study of crystalline fish lenses Laser Microscope objective Eye lens in a glass cell Wave to test Reference wave HDI plate Collimating lens (Observation plane) Experimental Measurements: Fish eye crystalline lens An on-going study: Fish eye crystalline lens measurement. The optical properties of the isolated crystalline lens determine its precise role in ocular optics. Vision of fish eyes is similar to terrestrial vertebrates like birds and mammals, but have a spherical lens. Their retinas generally have both rod cells and cone cells. Crystalline lens under test: Scorpion fish (Scorpaena Scrofa) Glass cell with the crystalline lens and the point diffraction plate. Noisy interferogram with some visible fringes. Caustics computed from the first dark fringe Now we have added a spherical wave centred at a certain height yp. An intensity detector can register the interferences A point object (pin-hole) diffracts light into a perfect spherical wave. Interferograms obtained at different heights y0 corresponding to heights yp of the point-diffractometer