We present a quantum-state reconstruction procedure to retrieve a rotational wave packet created via nonadiabatic excitation by ultrashort pulses with controlled polarization. Here a unidirectionally rotating ensemble of CO molecules, adiabatically cooled to be populated only in $J$ = 0 as an initial state, has been prepared by skewed-polarization pulse-pair excitation. The two-dimensional sections of the molecular-axis probability distribution have been captured by time-delayed Coulomb explosion with the space-slice ion-imaging setup, recently developed in the present research group [K. Mizuse, R. Fujimoto, and Y. Ohshima, Rev. Sci. Instrum. 90, 103107 (2019)]. The time- and angle-dependent distribution has been subjected to the least-squares regression to provide a unique set of the amplitudes and phases for the eigenstates that constitute the wave packet. The reconstruction allows us to make a movie of the three-dimensional probability distribution and evaluate any physical properties, e.g., the magnitude of rotational angular momentum and its degree of orientation. The determined phases also serve as a sensitive probe for the excitation and the quantum interference to control the directionality of the rotational wave packet.

中文翻译：

---

单向分子旋转的量子态重构

我们提出了一种量子态重建程序，以检索通过具有受控极化的超短脉冲通过非绝热激发而创建的旋转波包。在此，CO分子的单向旋转集合绝热冷却，仅填充到$Ĵ$通过偏极化脉冲对激励准备了= 0作为初始状态。分子轴概率分布的二维截面已通过时空库仑爆炸和空间片离子成像装置捕获，该研究是本研究小组最近开发的[K. Mizuse，R。Fujimoto和Y.Ohshima，Rev。Sci 。仪器 90，103107（2019）]。对时间和角度相关的分布进行了最小二乘回归，以提供构成波包的本征态的一组唯一的振幅和相位。重构使我们能够制作三维概率分布的电影，并评估任何物理属性，例如旋转角动量的大小及其取向程度。所确定的相位还用作激发和量子干扰的灵敏探针，以控制旋转波包的方向性。