Optical vortex filtering for the detection of electromagnetically induced transparency

Abstract

We report on the realization of an optical filter based on an optical vortex mask designed to exclusively detect a weak coherent laser field in the presence of a much stronger, nearly spatially overlapping field. We demonstrate the performance of such an optical vortex filter to eliminate the strong control field and detect only a weak optical field's transmission under the conditions of electromagnetically induced transparency. The attractive feature of such a filter is its insensitivity to optical field frequencies and polarizations, which makes it applicable for a wide range of coherent processes.