In order to develop a laser system for multi-wavelength satellite laser ranging,the joint group of the Shanghai Astronomical Observatory and the Czech Technical University has studied the conversion efficiency of the Raman-shifting beam and its spatial characteristics.We adopted a 0.53 μm laser with pulse width of 35 ps and peak energy of 35 mJ,the second harmonic of a Nd:YAG actively and passively mode-locked laser,to pump a one-meter-long Raman tube which is full of H2 with high pressure at the Prague-based laboratory.We get the first Stokes laser (0.68 μm):7 mJ (single pulse) with beam divergence of 40" (arcsecond) and spatial wobbling of less than 4";and the first anti-Stokes laser (0.43 μm):2 mJ (single pulse) with divergence of 56" and spatial wobbling of less than 4".The emitting beam from the Raman cell also includes 0.53μm:10 mJ (single pulse) with divergence of 40" and spatial wobbling of less than 7".According to the radar link equation and based on the above on the above obtained multi-wavelength’s energy,we can estimate the detection probabilities for three colors respectivelyl.It is shown by the result that the developed multi-wavelength Raman laser system has the capability of satellite ranging.The Raman laser system will be installed at the laser station in Shanghai Astronomical Observatory to research the multi-wavelength satellite laser ranging.
