Abstract
We propose an approach based on geometric phase for performing several types of shearing interferometry through a robust, compact, common-path setup. The key elements are two identical parallel plates with spatially varying birefringence distributions, which perform the shearing by writing opposite geometric phases on the two circular polarization components of the linearly polarized incident wavefront. This setup allows the independent control of the shearing magnitude and relative phase of the two wavefront replicas. The approach is first illustrated for the simplest case of lateral shearing, and then extended to other geometries where the magnitude and direction of the shear vary smoothly over the wavefront.
Highlights
Shearing interferometry via geometric phaseA final example, shown, corresponds to the measurement of the helicoidal wavefront of a hypergeometric-Gaussian beam [27] resulting form the passage of a Gaussian beam through a q-plate [23] (a Spatially Varying Axis birefringent Plates (SVAPs) whose optic axis distribution has a topological charge q, equal to unity in this case)
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We propose an approach based on geometric phase for performing several types of shearing interferometry through a robust, compact, common-path setup
Summary
A final example, shown, corresponds to the measurement of the helicoidal wavefront of a hypergeometric-Gaussian beam [27] resulting form the passage of a Gaussian beam through a q-plate [23] (a SVAP whose optic axis distribution has a topological charge q, equal to unity in this case) The phase of this waverfront is Φ(x, y) = φ = arctan(x, y), the azimuthal angle. Extension to radial and other geometries – An important feature of SVAP-based shearing is the freedom it provides for implementing different geometries, as discussed in the Supplement 1 This is illustrated by replacing the Λ-plates with two Geometric Phase Lenses (GPLs), so that the interferometer performs a radial shear, resulting from the interference of two differently sized replicas of the test beam (Fig. 6). Details of the method will be provided in a upcoming work
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