IR LASER DETECTOR

PURPOSE:To obtain an IR laser detector effective for a wide range of IR light in which drift in the luminance is eliminated by making a plate from a powder of such material as emitting second harmonic scattering light intensely under powdery state. CONSTITUTION:A material emitting second harmonic scattering light intensely under powdery state includes ADP, KDP, KTP, LiNbO3, LiTaO3, for example. When a plate is made of a powder material 3, the powder material 3 having an appropriate particle size is sandwiched compactly by two transparent substrates 1 through a spacer 2. Alternatively, the powder 3 is dispersed into a molten liquid or solution of a transparent polymer(e.g. acrylic resin) and then the solution is cooled or dried thus fixing the powder into the polymer. Preferably, the powder 3 has average particle size substantially equal to the average coherent length (a) (several hundreds mum-several tens mum) for a material 5 which can be phase matched and equal to several hundreds mum or above for a material 4 which can not be phase matched.