玻色-费米气体量子简并光学偶极阱的设计

实现了将预冷却(温度约为1～2μK)的87 Rb和40 K原子装载到远红失谐的光学偶极力阱中,继而利用逐步降低光强的方法对其进行蒸发冷却,获得了87 Rb原子的玻色-爱因斯坦凝聚(BEC),并用协同冷却的方法得到了40 K原子的量子简并(DFG)。实验上通过光纤传输远红失谐激光束降低了光束指向性的抖动,又利用光强反馈伺服系统抑制远红失谐激光的强度抖动,提高了获得玻色-爱因斯坦凝聚和简并费米气体的重复性和稳定性。实验上得到玻色-爱因斯坦凝聚的原子数达8.48×105个,简并费米气体的原子数量约为3.34×106个。

The Design of a dipole traps for Bose-Einstein Condensate and Degenerate Fermi Gas

We create a Bose-Einstein condensate (BEC) of 87Rb atoms and a Degenerate Fermi gas (DFG) of 40K atoms by evaporative cooling in an optical trap. Two optical fibers were used to transmit 1064 nm-laser beams from optical platform to science platform to avoid pointing shaking. And these very two beams were controlled by two feedback systems, respectively, so that the power of each beam can be controlled accurately. By these two means, we got a very stable optical dipole trap for Bose-Einstein condensate and Degenerate Fermi Gas and the repetitiveness of our system had been improved remarkably. The pure condensate with up to 8.48×105 87Rb atoms is obtained over 1.6 s by lowering the power of the trap beams. Simultaneously, we got 3.34×106 40K atoms in Degenerate Fermi Gas.