实验中通过互组跃迁689 nm激光抽运形成三重态最低能态原子布居,引入688 nm激光改变三重态最低能态间的原子布居,利用抽运光与探测光空间分离的方法观测碱土金属锶原子的三重态能态间跃迁(5s6s)^3S1 → (5s5p)^3Pj(j=0,1,2)的吸收谱线,对应三条跃迁线的激光波段为679 nm, 688 nm和707 nm.探测三重态原子跃迁谱线可以用于锶原子冷却中再抽运光707 nm和679 nm激光频率的直接锁定,相比于通常利用的腔传递技术,可以把再抽运光频率锁定在原子跃迁谱线上,有利于提高锶原子冷却中俘获原子数目的长期稳定性.
In this paper we present a method of observing triplet state transitions of strontium. The intercombination transition is employed to pump the atom population from singlet-state (5s2)^1S0 to triplet-state (5s5p)^3P1 by a laser at 689 nm. Then 688 nm laser is also employed to divide atom population into the two other triplet-state states (5s5p)^3P0 and (5s5p)3PP2. We can obtain the absorption signals of triplet-state transition (5s6s)^3S1 → (5s5p)^3P0 and (5s6p)^3S1 → (5s5p)^3P3P2. And these atomic absorption signals can be used for stabilizing the repumping light 679 nm and 707 nm directly to transition line of strontium. This method can be used in the Doppler cooling of strontium atoms.