Narrow-line laser cooling by adiabatic transfer
Narrow-line laser cooling by adiabatic transfer
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DOI：
10.1088/1367-2630/aaa950
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发表时间：
2017-07
影响因子：
3.3
通讯作者：
M. Norcia;J. R. Cline;J. Bartolotta;M. Holland;J. K. Thompson
中科院分区：
文献类型：
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作者：
M. Norcia;J. R. Cline;J. Bartolotta;M. Holland;J. K. Thompson
我们提出并证明了一种新的激光冷却机制，适用于窄线宽的光学跃迁的粒子。通过对反向传播的激光束进行频率扫描，我们在基态和长寿命的光激发态之间来回产生绝热转移。这些绝热转移的时间顺序由多普勒频移决定，多普勒频移确保了相关的光子反冲与粒子的运动方向相反。这最终导致了一个强大的冷却机制，能够施加大的力量，通过一个弱的过渡和减少依赖于自发辐射。我们提出了一个简单直观的模型所产生的摩擦力，并直接证明其功效，增加原子系综的总相空间密度。我们依赖于模拟和实验研究，使用7.5 kHz的线宽1S0到3P1过渡88锶。减少对自发发射的依赖可以允许这种绝热扫描方法成为用于冷却缺乏闭合循环转变的粒子（诸如分子）的有用工具。
We propose and demonstrate a novel laser cooling mechanism applicable to particles with narrow-linewidth optical transitions. By sweeping the frequency of counter-propagating laser beams in a sawtooth manner, we cause adiabatic transfer back and forth between the ground state and a long-lived optically excited state. The time-ordering of these adiabatic transfers is determined by Doppler shifts, which ensures that the associated photon recoils are in the opposite direction to the particle’s motion. This ultimately leads to a robust cooling mechanism capable of exerting large forces via a weak transition and with reduced reliance on spontaneous emission. We present a simple intuitive model for the resulting frictional force, and directly demonstrate its efficacy for increasing the total phase-space density of an atomic ensemble. We rely on both simulation and experimental studies using the 7.5 kHz linewidth 1S0 to 3P1 transition in 88Sr. The reduced reliance on spontaneous emission may allow this adiabatic sweep method to be a useful tool for cooling particles that lack closed cycling transitions, such as molecules.