<title>ZnGeP<formula><inf><roman>2</roman></inf></formula> crystal: applications for visualization or IR signals</title>

Abstract

Up-conversion of long, 3-5O-ts, pulses imitating input signals of CO2 laser differential absorption lidars was investigated experimentally. Efficiency of 1 to 2% has been achieved when using 1.06-pm Nd:YAG pump emission and 3.9 mm ZnGeP2 crystal that is characterized by absorption coefficient equal to 2.0 cm' at this wavelength and 2.5cm' at up-converted 0.9548 m one. When using a silicon avalanche photodiode operating in photon counting mode operation, 450 times increase in signal-to-noise ratio can be realized in comparison with direct detection of the CO2 laser lidar signals by MCT photodiode.