摘要： We report the preparation of a 780.2 nm and 852.3 nm laser device based on single-pass periodically poled magnesium-oxide-doped lithium niobate (PPMgO:LN) bulk crystals and diode-laser-seeded fiber amplifiers. First, a single-frequency continuously tunable 780.2 nm laser of more than 600 mW from second-harmonic generation (SHG) by a 1560.5 nm laser can be achieved. Then, a 250 mW light at 852.3 nm is generated and achieves an overall conversion efficiency of 4.1% from sum-frequency generation (SFG) by mixing the 1560.5 nm and 1878.0 nm lasers. The continuously tunable range of 780.2 nm and 852.3 nm are at least 6.8 GHz and 9.2 GHz. By employing this laser system, we can conveniently perform laser cooling, trapping and manipulating both rubidium (Rb) and cesium (Cs) atoms simultaneously. This system has promising applications in a cold atoms Rb-Cs two-component interferemeter and in the formation of the RbCs dimer by the photoassociation of cold Rb and Cs atoms confined in a magneto-optical trap.