Measuring the topological charge of coherence vortices through the geometry of the far-field cross-correlation function.

Determination of orbital angular momentum of optical vortex beams has attracted the attention of many researchers over the last few years. For some applications, it is convenient to use a partially coherent vortex beam because of its robustness. In this work, we developed a method to measure the topological charge of a partially coherent vortex beam. Our method relies simply in the measurement of the minimum radius of a zero contour of the modulus of the cross-correlation function and in the measurement of the full width at half maximum of its central spot.

Sorting of spatially incoherent optical vortex modes.

Coherent optical vortices have promising applications in quantum and classical optical communication. They add new degrees of freedom to code information. In this context, to implement a tool enabling sorting of spatially multiplexed vortex states is fundamental. By other hand, spatially incoherent vortices can be more robust in propagation through noise media, such as turbulent atmosphere or obstacles that block part of the light. Therefore, in this work we propose directly applying a high-resolution sorting scheme to spatially incoherent vortex states.

Method to define non-diffracting optical beams mimicking the shape of simple plane curves.

We theoretically and experimentally demonstrate a method to define non-diffracting beams with different geometries. Our findings constitute an alternative to current methods for finding non-diffracting beams, which rely on the solution of the wave equation in a given coordinate system that has a limited number of possibilities or uses a complicated and time-consuming optimization algorithm. Therefore, the method is easier to follow, because it does not require optimization and allows one to obtain non-diffracting beams mimicking the geometry of simple plane curves. The method could find applications in manipulation of matter with optical waves, such as colloidal and living particles, and in quantum, nonlinear, and atom optics.