Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany.
The Hamburg Center for Ultrafast Imaging, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
Phys Rev Lett. 2015 Mar 13;114(10):103003. doi: 10.1103/PhysRevLett.114.103003. Epub 2015 Mar 10.
We demonstrate strong laser-field-free orientation of absolute-ground-state carbonyl sulfide molecules. The molecules are oriented by the combination of a 485-ps-long nonresonant laser pulse and a weak static electric field. The edges of the laser pulse create a coherent superposition of two rotational states resulting in revivals of strong transient molecular orientation after the laser pulse. The experimentally attained degree of orientation ⟨cosθ⟩≈0.6 corresponds to the theoretical maximum for mixing of the two states. Switching off the dc field would provide the same orientation completely field free.
我们展示了强激光场自由取向的绝对基态羰基硫分子。分子通过一个 485 皮秒长的非共振激光脉冲和一个弱静电场的组合来实现取向。激光脉冲的边缘产生了两个旋转态的相干叠加，导致激光脉冲后强瞬态分子取向的复兴。实验获得的取向度 ⟨cosθ⟩≈0.6 对应于两种状态混合的理论最大值。关闭直流场将完全无场提供相同的取向。
