A two-stage up-convertor made of AgGaSe2 and beta-BBO crystals

A two-stage infrared up-convertor made of AgGaSe2 and beta-BBO crystals has been built up, that can up-convert the mid-infrared radiation of 11-16 mu m into the 0.8-mu m range where the sensitive photomultiplier can be used. This up-convertor is pumped with a near-infrared radiation of 1.7-1.8 mu m wavelength range generated by a beta-BBO optical parametric oscillator. In this experiment, we also measured the o-ray refractive index of AgGaSe2 in the 11-16 mu m mid-infrared range and extended the fitting range of the Sellmeier equation to the 16-mu m wavelength range.