Dynamical Laser Cooling of Ultranarrow Linewidth Atoms and Molecules

这个理论研究项目探索了一个新的令人兴奋的想法，即使用激光将原子和分子冷却到比深太空低100万倍以上的温度。这种创新的技术被称为交换冷却，它使用了非常相干的激光，其纯色是周期性调制的。这项新技术最初是实验室中的一项偶然的实验发现，它有望推动操纵和控制量子气体所取得的成就的前沿，从而在科学和技术方面有广泛的潜在应用。这并不是第一个激光冷却的提议；事实上，在过去的二三十年里，使用激光控制和冷却原子气体的想法已经得到了广泛的探索，并导致了原子物理实验室每天使用的许多方法的发展。然而，这种新方法有可能大幅扩大可用于量子科学和量子计算应用的原子和分子的范围，并提供改进最先进的原子钟(用于GPS卫星导航等系统)的机会。这个新的想法是基于这样一个前提，即具有两个价电子的系统(第二族元素和其他类似的原子和分子系统)提供的极端相干为激光科学提供了一个新的令人兴奋的前沿。在这些系统中，极弱的偶极跃迁的存在使得传统的激光冷却方法的实施变得困难，部分原因是对激光频率的严格的稳定性要求。这里的新想法是，可以使用其强度或频率可以随时间调制的近共振激光场。这可能会放大强相干力的影响，同时降低光子的耗散和自发散射的作用，否则会增加可实现的温度。其目标是，比方说，实现频率标准提高十倍，直接转化为当前技术的潜在重大改进，从改进的计量，到先进的通信，再到下一代导航和定位系统的精密设备。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This theoretical research project explores a new and exciting idea where lasers are used to cool atoms and molecules to temperatures more than a million times colder than deep space. This innovative technique, dubbed SWAP cooling, employs extremely coherent lasers whose pure color is periodically modulated. Starting first as an accidental experimental discovery in the laboratory, this new technique promises to push back the frontier of what can be achieved in manipulating and controlling quantum gases, and to thereby have a broad range of potential applications in science and technology. This is not the first laser-cooling proposal; indeed the idea for using lasers to control and cool atomic gases has been explored extensively over the past two or three decades, and has led to the development of many methods that are used every day in atomic physics laboratories. However, this new approach has the potential to massively expand the range of atoms and molecules that can be considered for quantum science and quantum computation applications, and offers to improve state-of-the-art atomic clocks (used in such systems as GPS satellites for navigation). The novel idea is based on the premise that the extreme coherence offered by systems that have two valence electrons (group-II elements and other similar atomic and molecular systems) offers a new and exciting frontier for laser sciences. In these systems, the presence of extremely weak dipole transitions causes the implementation of traditional laser-cooling approaches to be difficult due in part to the demanding stability requirements for the laser frequencies. The new idea here is that near-resonant laser fields can be used whose intensity or frequency may be modulated in time. This may amplify the effects of strong coherent forces while simultaneously reducing the role of dissipative and spontaneous scattering of photons that would otherwise increase the realizable temperatures. The aim is to achieve, say, a ten-fold improvement in frequency standards that translates directly into potential major improvements in current technologies, ranging from improved metrology, to advanced communication, to the next generation of precision devices for navigation and positioning systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.