Large optical nonlinearities near the bandgap of MOCVD-grown GaN thin films

Summary form only given.To study the effects of high densities of excess free carriers on the optical transitions near the band edge of wurtzite GaN, nondegenerate nanosecond optical pump-probe transmission and reflection experiments have been performed on GaN thin films grown by metallo-organic chemical-vapor deposition (MOCVD) on (0001)-oriented sapphire. The large magnitude of the optical nonlinearities observed in our work suggests the possibility of new optoelectronic applications.