标题： 双色连续波激光场中的线性极性分子：对称性分析 显示英文标题

标题： A linear polar molecule in a two-color cw laser field: a symmetry analysis

摘要： 本文呈现了关于线性极性分子在双色非共振连续波激光场中旋转动力学的理论研究。通过系统地考虑该场与分子电偶极矩、极化率和超极化率的相互作用，探索了哈密顿量对称性对取向和排列的影响，这在时间平均近似不成立的条件下尤为显著。研究表明，取向和排列满足某些对相位和场强的对称性。平均而言，单一频率连续波激光场不会使分子取向，需要具有奇偶激光频率乘积的双色场来打破头尾顺序限制。 显示英文摘要

摘要： A theoretical study of the rotational dynamics of a linear polar molecule in a two-color non-resonant cw laser field is presented. By systematically considering the interactions of this field with the electric dipole moment, polarizability and hyperpolarizability of the molecule, the effect of the symmetries of the Hamiltonian on the orientation and alignment is explored in a regime where the time-average approximation does not hold. It is shown that the alignment and orientation satisfy certain symmetries as a function of the phases and field strengths. On average a one-color cw laser field doest not orient the molecule, being necessary a two-color one having odd and even products of the laser frequency to break the head-versus-tail order confinement.