Cascading nonlinearities in an organic single crystal core fiber: the Čerenkov regime

Abstract

The large nonlinear phase shifts imparted to the fundamental beam during Čerenkov second harmonic generation (SHG) in a DAN, 4-(N,N-dimethylamino)-3-acetamidonitrobenzene, single crystal core fiber are explained and modelled numerically. Cascading upconversion and downconversion processes leads to nonlinear phase shifts produced by the second order nonlinear coupling of the guided fundamental mode and the component of the Čerenkov second harmonic field trapped in the fiber cladding.