Generalized angular momentum transfer to up-converted photons via four-wave mixing in atomic gases

Abstract

Experimental results on the phase transfer from structured beams to parametric light, generated by inducing four-wave mixing in an atomic gas, are reported. Near-infrared, Mathieu, and Gaussian pump beams yield a blue coherent Mathieu electromagnetic field and an infrared beam. Two complementary techniques enable full characterization of the up-converted modes. The unambiguous and efficient phase heritage of these complex quasipropagation invariant modes to up-converted photons is demonstrated. The presented data enable a quantitative study of dynamical variables related to Mathieu beams. These include elliptic angular momentum, a generalization of the orbital angular momentum of light, which is also up-converted through the nonlinear process.