Measuring the complex amplitude of speckle fields by means of a shear interferometer

• Autores: Claas Falldorf, Christoph von Kopylow, Ralf B. Bergmann
• Localización: SPECKLE 2012: V International Conference on Speckle Metrology : 10-12 september 2012 : Vigo, Spain / Ángel Manuel Fernández Doval (ed. lit.), María Cristina Trillo Yáñez (ed. lit.), José Carlos López Vázquez (ed. lit.), 2012, ISBN 9780819490902
• Idioma: inglés
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• Resumen

  • We present a method to recover the complex amplitude of speckle fields from measurements performed by a shear interferometer. In contrast to the state of the art, it requires only two measurements with the orientation of the shears selected to be orthogonal to each other, while the respective magnitudes correspond to a unit camera pixel. The evaluation comprises an iterative local optimization procedure using the steepest descent gradient algorithm in combination with an heuristic initial guess. The algorithm finds a local minimum least squares solution even in the presence of branch points and camera noise. To demonstrate the approach, light scattered by a diffuser is investigated. The results are shown to agree well with those obtained from a standard interferometric technique