Collisionally induced laser cooling of ultradense molecular gases

虽然激光冷却原子是一项非常成功的技术，但到目前为止，这种分子冷却一直是一个难以实现的目标。该项目的目的是通过实验演示超稠密分子气体的激光冷却。我们将使用一种补充早期方法的技术，并在高压环境中使用激光诱导的跃迁，频繁的分子与缓冲气体碰撞将分子跃迁转换为与高度失谐的激光光束的共振，而自发衰变发生在接近未受扰动的跃迁频率。在这样的激发循环中，我们预计动能和内部分子能量将从探针系综中提取。在初步实验中，我们的团队已经成功地演示了用Rb原子和230巴的Ar缓冲气体对超稠密原子系综进行碰撞再分布冷却。由于分子具有复杂的振动和分子结构，在高压缓冲气体环境中的特性还有待研究，因此再分布冷却在分子中的应用还需要深入的研究。我们展望了再分布冷却在分子量子物理和一种新型化学中诱人的应用。其他应用可以包括光学制冷器。

While laser cooling of atoms is a very successful technique, such cooling of molecules has so far been an elusive goal. The aim of this project is to experimentally demonstrate the laser cooling of an ultradense molecular gas. We will use a technique that is complementary to earlier approaches and uses laser-induced transitions in a high pressure environment, with frequent molecule-buffer gas collisions shifting molecular transitions into resonance with a highly red detuned laser beam, while spontaneous decay occurs close to the unperturbed transition frequency. In such excitation cycles, we expect kinetic and internal molecular energy to be extracted from the probe ensemble. In preliminary experiments, our group has successfully demonstrated collisional redistribution cooling for an ultradense atomic ensemble with rubidium atoms and 230 bar of argon buffer gas. Due to the complex vibrational and molecular structure, whose characteristics in a high pressure buffer gas environment remain to be investigated, the application of redistribution cooling to molecules requires intense research. We foresee tantalizing applications of redistribution cooling in molecular quantum physics and a novel type of chemistry. Other applications can include optical chillers.