Lasers with high spectral purity are indispensable for optical clocks and for the coherent manipulation of atomic and molecular qubits in applications such as quantum computing and quantum simulation. While the stabilization of such lasers to a reference can provide a narrow linewidth, the widely used diode lasers exhibit fast phase noise that prevents high-fidelity qubit manipulation. In this paper, we demonstrate a self-injection locked diode laser system that utilizes a high-finesse cavity. This cavity not only provides a stable resonance frequency, it also acts as a low-pass filter for phase noise beyond the cavity linewidth of around 100 kHz, resulting in low phase noise from dc to the injection lock limit. We model the expected laser performance and benchmark it using a single trapped ⁴⁰Ca⁺-ion as a spectrum analyzer. We show that the fast phase noise of the laser at relevant Fourier frequencies of 100 kHz to >2 MHz is suppressed to a noise floor of between −110 dBc/Hz and −120 dBc/Hz, an improvement of 20 to 30 dB over state-of-the-art Pound-Drever-Hall-stabilized extended-cavity diode lasers. This strong suppression avoids incoherent (spurious) spin flips during manipulation of optical qubits and improves laser-driven gates when using diode lasers in applications involving quantum logic spectroscopy, quantum simulation, and quantum computation.

中文翻译：

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用于原子物理实验的低相位噪声腔传输自注入锁定二极管激光系统

具有高光谱纯度的激光器对于光学时钟以及量子计算和量子模拟等应用中原子和分子量子位的相干操纵是必不可少的。虽然这种激光器相对于参考的稳定可以提供窄线宽，但广泛使用的二极管激光器表现出快速相位噪声，阻碍了高保真量子位操作。在本文中，我们展示了一种利用高精细腔体的自注入锁定二极管激光系统。该腔不仅提供稳定的谐振频率，还充当超过腔线宽约 100 kHz 的相位噪声的低通滤波器，从而实现从直流到注入锁定极限的低相位噪声。我们对预期的激光性能进行建模，并使用单个捕获的⁴⁰ Ca ⁺离子作为光谱分析仪对其进行基准测试。我们表明，在 100 kHz 至 > 2 MHz 的相关傅立叶频率下，激光器的快速相位噪声被抑制至 -110 dBc/Hz 至 -120 dBc/Hz 之间的本底噪声，比状态下提高了 20 至 30 dB最先进的 Pound-Drever-Hall 稳定扩展腔二极管激光器。这种强抑制避免了光学量子位操作过程中的不相干（虚假）自旋翻转，并在涉及量子逻辑光谱、量子模拟和量子计算的应用中使用二极管激光器时改进了激光驱动门。