High-efficiency conversion of infrared into visible radiation in an LiNbO3 crystal

An investigation was made of the conversion of infrared into visible radiation in an LiNbO₃ crystal. This was done by mixing infrared radiation with that produced by a pulse ruby laser. Infrared radiation of wavelengths 1.6–3 μ was converted by the оое interaction using different phase-matching angles. A quantitative dependence of the converted-radiation power on the laser pump power was obtained. The converted-radiation power reached saturation for a pump power density of 5 MW/cm² when the phasematching angle was 90° and the conversion took place in a 2-cm long crystal.