Second harmonic generation with full Poincaré beams

We report a concise yet efficient experiment to extend the study of full Poincaré beams to incorporate the nonlinear optical effect. The main feature of our scheme is the employment of Type-II phase-matching KTP crystal to implement the second harmonic generation with structured vector light from invisible to visible region. Of particular interest is the revelation and visualization of the hidden topological structures transferred from the input polarization state to the output observable intensity patterns. The experimental results are in good agreement with the numerical simulations. Our present work provides us with the insight into the interaction of full Poincaré beams with media in the nonlinear regime.