利用蓝失谐激光诱导微型光学偶极阱中冷原子间的光助碰撞提高单原子制备概率

借助于微米尺度的远失谐光学偶极阱(FORT)中蓝失谐光的光助碰撞效应与反馈控制系统,文章在实验上实现了FORT中单个原子的高效制备.结合原子的势能曲线,分析了原子在红失谐光和蓝失谐光作用下的光助碰撞效应,并且在实验上得到红失谐光诱导下单原子的制备概率约50%,蓝失谐光诱导下单原子的制备概率约80%.通过反馈控制系统,当原子数目小于1时,反馈控制使磁场梯度减小以快速俘获原子,当原子数目大于1时,反馈控制开启蓝失谐光场,使得原子一个个逃逸出阱中,最终实现了FORT中单原子的制备概率约95%,为下一步偶极阱的二维扩展奠定了基础.通过HBT实验测量FORT中单原子发出光子的统计特性,得到二阶相干度g(2)(τ=0)=0.08.

Improving the single atom probability by using the blue-detuned laser-assisted-collisions between the cold atoms trapped in the for-off-resonance trap

Using the light-assisted-collisions (LAC) and the feedback controlling loop on a quadrupole magnetic field, we have realized high probability of single atoms in the far-off-resonance trap (FORT). We analyzed the principle of LAC irradiated by a red-detuning laser or by a blue-detuning laser. And we also experimentally proved that using the red-detuned laser (the blue-detuned laser) we can realize 50% (80%) of single atom probability in the FORT. Using the feedback controlling loop, we realized 95% of single atom probability in the FORT, which opens a way for a two-dimensional FORT array. When the number of atom was zero, we decreased the gradient of the quadrupole magnetic field to quickly load atoms, and when we had more than one atom in the FORT, we switched on the blue-detuned laser to irradiate the atoms to play LAC. We measured the second-order coherence degree of the fluorescence photons emitted by the atom trapped in the FORT by using HBT scheme and found it was g⁽²⁾(τ=0)=0.08.