利用双光子吸收机制，以778 nm染料激光器作为抽运源，以碱金属Rb蒸气作为增益介质，成功获得了420 nm的蓝光激光输出。以Rb原子能级结构为基础，对其产生蓝光的机理和双光子吸收机制进行了分析描述。基态52S1/2能级的Rb原子通过吸收两个778.1 nm的光子跃迁到激发态52D5/2能级，通过辐射中红外光子跃迁到激光上能级62P3/2，与基态52S1/2能级形成粒子布居数反转,产生420 nm蓝色激光。对激光二极管抽运碱金属蓝光激光器的发展前景进行了展望。

Based on two-photon absorption and pumped by a 778.1 nm dye laser, a 420 nm blue laser is achieved by using alkali Rb vapor as gain medium. Utilizing the energy level structure of Rb atom, blue laser mechanism and two-photon absorption process are analysed. By absorbing two 778.1 nm photons, Rb atoms are transitted from ground state 52S1/2 to excited state 52D5/2, then to laser up state 62P3/2 and ground state 52S1/2 populating inversion is fromed through radiating mid-infrared photon. The 420 nm blue laser is achieved through 62P3/2 to 52S1/2. The development prospect of laser diode pumped alkali vapor blue laser is expected.