銣85原子在光偶極阱的超冷碰撞

Ultracold collision of Rubidium 85 in a crossed dipole trap

陳弘斌(Hong-bin Chen)

指導教授 ： 劉怡維

國立清華大學/理學院/物理學系/碩士(2012年)

https://doi.org/10.6843/NTHU.2012.00395

摘要

本實驗研究85Rb原子與85Rb2分子在光偶極阱中的碰撞，透過吸收影像法量測85Rb F=2原子團的生命周期，來觀察原子與分子碰撞的行為，估計在光偶極阱中85Rb2分子的數量。在實驗中，使用非單頻的高功率Fiber雷射 (波長1080 nm,輸出功率為20W) 作為光偶極阱的光源，並透過成像系統，做了螢光法與吸收影像法，對Crossed dipole trap中的銣原子做基本量測。在系統中，光偶極阱約載到了1.13x105個原子，平均密度約9.7x1011個/cm3，在基態F=3的原子團溫度約在400 ，生命週期小於100 msec；在基態F=2的原子團溫度約44 ，生命周期約100msec~200msec。透過光結合的方法產生85Rb2分子，同時與存在85Rb的原子團載入光偶極阱中，此時量測85Rb(F=2)原子團生命週期約78msec。

關鍵字

光偶極阱 ； 銣原子 ； 光結合 ； 磁光陷阱 ； 極冷原子 ； 極冷分子

並列摘要

In experiment, we observe 85Rb atoms and 85Rb2 molecules collision in crossed dipole trap by using absorption image method to measurement the Rb atoms lifetime and calculate the numbers of 85Rb2 molecules in a crossed dipole trap. We use high power laser (non-single frequency Fiber laser, 1080 nm, 20W) for a laser source of crossed dipole trap. The crossed dipole trap can be seen from CCD image system, we use absorption image and fluoresce method to measure lifetime, atom number, and temperature in a crossed dipole trap. The number of atoms in crossed dipole trap is about 1.13x105 atoms, the average density is atom/cm3.The atoms in ground state F=3, the temperature is about 400 and the life time less than 100 msec. The atoms in ground state F=2, the temperature is about 44 and the lifetime is 100~200 msec. By using photoassociation method to generate 85Rb2 molecules, and load in crossed dipole trap with Rb atoms at the same time, the lifetime of atom in ground state (F=2) is 79msec.

並列關鍵字

crossed dipole trap ； Rubidium ； photoassociation ； magneto optical trap ； ultracold molecular ； ultracold atom

參考文獻

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