University of Twente Student Theses


Measuring local phase gradients through Partitioned Aperture Wavefront (PAW) imaging.

Reuling, Jeffrey (2015) Measuring local phase gradients through Partitioned Aperture Wavefront (PAW) imaging.

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Abstract:We demonstrate the first experimental result of the partitioned aperture wavefront (PAW) technique in conjunction with coherent light illumination. PAW enables noninterferometric, single shot phase gradient measurements in contrast to other phase detection methods that require a reference arm and/or long time measurements. The partitioned aperture technique was originally designed for use in a bright-field microscope and uses lenses that are cut and glued together to focus a single collimated beam into four images. We first build a microscope, in both transmission and re ection, and did measurements on samples with known phase gradients. Our data matches the expectations with an error of 2.5 mrad and 0.09 mrad in the transmission and re ection measurements respectively. We then switch to a coherent light source, a He-Ne laser, and insert a scanning mirror into the setup. This scanning mirror is used to avoid the center of the four lenses and avoid the error it would cause. Here we also use a sample with a known phase gradient, resulting in data that matches our expectations with an error of 0.43 mrad.
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Subject:33 physics
Programme:Applied Physics MSc (60436)
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