Self-waveguided blue light emission in p-sexiphenyl crystals epitaxially grown by mask-shadowing vapor deposition

Highly polarized and self-waveguided blue light emission was observed in oriented organic crystals of p-sexiphenyl (6P). The 6P molecules were epitaxially grown in needlelike crystals with a submillimeter length by mask-shadowing vapor deposition on the KCl (001) surface. In the crystals, the molecular axes are oriented parallel to the [110] direction of the KCl substrate and perpendicular to the needle axis of the crystal. Under ultraviolet excitation, the blue light emission was confined within the crystal and self-waveguided along the needle axis with the transverse-electric mode, then radiated from the tips of the needles. This self-waveguided emission in the crystal was based on the uniaxially oriented transition dipoles which lay on the KCl surface and were aligned perpendicular to the needle axis in the crystal. (C) 1999 American Institute of Physics. [S0033-6951(99)00628-2].