Orientation dependent nonlinear optical effects in ZnSe nanowires

Abstract

Three nonlinear optical phenomena, two-photon induced luminescence, second-harmonic generation, and third-harmonic generation, were studied experimentally in ZnSe nanowires. All three effects demonstrate a strong dependence on the orientation of linearly polarized excitation, being maximal for the polarization parallel to the nanowire axis. The phenomenon is caused by the anisotropic nanowire depolarization due to the difference in dielectric constants between the nanowires and the environment and has different amplitude for nanowires embedded in different dielectrics. The amplitude depends also on nanowire bending and nonuniformity.