Determination of the topological charge of a twisted beam with a Fresnel bi-prism
نویسندگان
چکیده
The self-interference pattern of a Laguerre Gaussian beam using a Fresnel bi-prism is shown to be very different from what could be expected from a usual laser beam. Actually it resembles the interference pattern that could be obtained using a double slit experiment. The interferences are shifted and the topological charge and its sign can be readily determined considering the shift order of the pattern only. However, since there is no diffraction nor absorption loses unlike in a double slit interference, such a set up could be used even for low power twisted beams or beams with high topological charge. Even fractional topological charges could be determined with an absolute precision of 0.05. PACS numbers: 42.50.Tx, 42.87.Bg, 42.50.Xa, 42.25.Hz
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