CERENKOV-RADIATION AND GUIDED-MODE BLUE 2ND-HARMONIC GENERATION IN 4-LAYER WAVE-GUIDES USING ORGANIC THIN-FILM CRYSTALS

Four-layer waveguide devices for second-harmonic generation were inves tigated by use of a new organic non-linear optical crystal, isopropyl- 4-acetylphenylurea. Blue second-harmonic generation in the form of the Cerenkov-radiation mode and the guided mode (from TE0omega to TE12 om ega) was demonstrated with a thin-film crystal of isopropyl-4-acetylph enylurea as a substrate. For the relaxation of the phase-matching cond ition and improvements in conversion efficiency, the thickness-noncrit ical phase-matching technique was introduced in the organic-inorganic hybrid four-layer waveguide geometry. (C) 1997 Optical Society of Amer ica.