High-Power Clock Laser Spectrally Tailored for High-Fidelity Quantum State Engineering

• Published in: Physical Review X
• Main Authors: Lingfeng Yan, Stefan Lannig, William R. Milner, Max N. Frankel, Ben Lewis, Dahyeon Lee, Kyungtae Kim, Jun Ye
• Format: Article
• Language: English
• Published: American Physical Society 2025-08-01
• Online Access: http://doi.org/10.1103/qw53-8b8r

Highly frequency-stable lasers are ubiquitous tools for optical-frequency metrology, precision interferometry, and quantum information science. While making a universally applicable laser is unrealistic, spectral noise can be tailored for specific applications. Here we report a high-power 698-nm clock laser with a maximum output of 4W and minimized frequency noise up to a few kHz Fourier frequency, together with long-term instability of 3.5×10^{-17} at one to thousands of seconds. The laser-frequency noise is precisely characterized with atom-based spectral analysis that employs a pulse sequence designed to suppress sensitivity to intensity noise. This method provides universally applicable tunability of the spectral response and analysis of quantum sensors over a wide frequency range. With the optimized laser system characterized by this technique, we achieve an average single-qubit Clifford gate fidelity of up to F_{1}^{2}=0.99964(3) when simultaneously driving 3000 optical qubits with a homogeneous Rabi frequency ranging from 10 Hz to 1 kHz. This result represents the highest single optical-qubit-gate fidelity for a large number of atoms.