Ultrabroadband generation of multiple concurrent nonlinear coherent interactions in random quadratic media

Abstract

Triply coincident nonlinear second harmonic interactions continuously tunable in an extremely large spectral range (800-1400 nm) are demonstrated in strontium barium niobate random quadratic crystal. The spectral dependence of the triple process is in agreement with a first order quasi-phase-matching collinear interaction. The analysis of the polarization states of the generated beams reveals mutually coherent interactions between different processes simultaneously contributing to the total intensity. The results constitute a necessary step in the implementation of ultra-broadband entangled photon pairs from randomly poled structures and are relevant to a wide range of applications, for which broadband polarization controlled light is required. © 2013 AIP Publishing LLC.