在本實驗中，我們首先設計一個新版本的光放大與光整形光路，用以改善光纖在同時擁有兩種不同波長 ( 766 nm 和 780 nm ) 的入射光下的耦合效率，藉此達到實驗所需之光強度。另外，為了得到比螢光法 ( fluorescence imaging method ) 更精確的原子數與原子密度量測，我們亦完成架設鉀原子系統的吸收影像法 ( absorption imaging method ) 光路。

首先，我們於磁光陷阱 ( magneto-optical trap ) 中捕捉了約 $2.3\times 10^{8}$ 個鉀原子，緊接著藉由亞都卜勒雷射冷卻 ( sub-Doppler cooling ) 的技術冷卻鉀原子至低於 200 $\mu$K，並將約 10\,\% 的原子載入磁陷阱 ( magnetic trap )，之後我們再將約 24\,\% 的鉀原子由磁陷阱磁轉移到 science cell，並以吸收影像法來量測並分析原子團。最終我們在 science cell 中得到約 $5.3\times 10^{6}$ 個鉀原子，其對應之溫度與生命週期分別約為 155 $\mu$K 與 32.44 秒。

此外，我們亦成功同時磁轉移 $1.8\times 10^{7}$ 個銣原子與 $3.1\times 10^{6}$ 個鉀原子至 science cell，其相對應之溫度分別為 133 $\mu$K 與 160 $\mu$K。因為在磁阱中異核原子的混合與碰撞會造成額外的損耗，所以鉀原子的生命週期降為約 27.06 秒。

In this work, we have designed a new version of power amplifier and beam shaping which have been employed successfully for cooling and repumping light after second tapered amplifier for better coupling efficiency of both potassium and rubidium simultaneously. We have also constructed the setup of absorption image technique for more accurate measurements.

In this experiment, $2.3\times10^{8}$ of cold potassium atoms were produced in the MOT, and about 10\,\% of them were loaded into the magnetic trap. The subsequent magnetic transferring to the science cell was achieved with a linear moving track and an efficiency of 24\,\%. After transferring to science cell, the lifetime increased to 32.44 s due to the reduced background collision.

Meanwhile, we also trapped and transferred $^{39}\rm{K}$ and $^{87}\rm{Rb}$ simultaneously to the science cell. The number is $3.1\times10^{6}$ with a temperature 160 $\mu$K for potassium and $1.8\times10^{7}$ with a temperature 133 $\mu$K for rubidium, respectively. Because of the additional loss caused by the inter-species collision, the lifetime of $^{39}\rm{K}$ was reduced to 27.06 s.

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