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Published on: March 22, 2019
Infrared vortex detection with nonlinear Young's double-slit interference
Abstract:
Different from the plane wave, the vortex beam passing through a Young's double slit will produce an interference pattern with lateral shear, where the degree of lateral shear is determined by the beam's topological charge, namely, providing a quantitative method for measuring the topological charge of vortex beams. However, limited by the detection efficiency, noise, and cost of infrared cameras, using Young's double-slit interference to measure infrared optical vortex modes remains relatively unexplored. Here, we construct a nonlinear Young's double slit, such that when an infrared optical vortex beam passes through it, interference fringes with lateral shear can be observed in the visible region. In our experiment, we successfully measured nine vortex modes with different topological charges using a visible camera, overcoming the performance limitations of infrared detectors. This scheme holds great promise for infrared vortex-encoded optical communications.
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