Schäfer Vera M, Niu Zhijing, Cline Julia R K, Young Dylan J, Song Eric Yilun, Ritsch Helmut, Thompson James K
JILA, NIST and Department of Physics, University of Colorado, Boulder, CO USA.
Max-Planck-Institut für Kernphysik, Heidelberg, Germany.
Nat Phys. 2025;21(6):902-908. doi: 10.1038/s41567-025-02854-4. Epub 2025 Apr 11.
Laser-cooled gases of atoms interacting with the field of an optical cavity are a versatile tool for quantum sensing and the simulation of quantum systems. These systems can exhibit phenomena such as self-organization phase transitions, lasing mechanisms, squeezed states and protection of quantum coherence. However, investigations of these phenomena typically occur in a discontinuous manner due to the need to reload atomic ensembles. Here we demonstrate hours-long continuous lasing from laser-cooled Sr atoms loaded into a ring cavity. The required inversion to produce lasing arises from inversion in the atomic-momentum degrees of freedom, which is linked to the self-organization phase transitions and collective atomic recoil lasing observed previously only in a cyclic fashion. We find that over a broad parameter range, the sensitivity of the lasing frequency to changes in cavity frequency is significantly reduced due to an atomic loss mechanism, suggesting a potential approach for mitigating low-frequency cavity noise. Our findings open opportunities for continuous cavity quantum electrodynamics experiments and robust and continuous super-radiant lasers.
与光学腔场相互作用的激光冷却原子气体是用于量子传感和量子系统模拟的通用工具。这些系统可以展现出自组织相变、激光机制、压缩态以及量子相干保护等现象。然而，由于需要重新加载原子系综，对这些现象的研究通常以不连续的方式进行。在此，我们展示了从加载到环形腔中的激光冷却锶原子实现长达数小时的连续激光发射。产生激光所需的反转源于原子动量自由度的反转，这与之前仅以循环方式观察到的自组织相变和集体原子反冲激光有关。我们发现，在很宽的参数范围内，由于一种原子损失机制，激光频率对腔频率变化的灵敏度显著降低，这表明了一种减轻低频腔噪声的潜在方法。我们的研究结果为连续腔量子电动力学实验以及稳健且连续的超辐射激光器开辟了机会。
