Polarization dependent two-photon properties in an organic crystal

The dependence of the fluorescence on the excitation beam polarization under two-photon excitation was studied in a 1,4-bis(R-cyano-4-diphenylaminostyry1)-2,5-diphenylbenzene organic crystal. The crystal shows strong response to the polarization, especially when the pump intensity was increased. The polarization plays an important role on the threshold of amplified spontaneous emission (ASE) and the Delta G(ASE) under two-photon excitation (TPE). Moreover, the polarization distribution between the TPE (800 nm) and one-photon excitation (400 nm) are very different. The former generates a cos(4) theta distribution, while the later gives rise to cos(2) theta distribution in different orientation. (C) 2010 American Institute of Physics. [doi:10.1063/1.3486683]