Camenzind Sandro L, Lang Lukas, Willenberg Benjamin, Pupeikis Justinas, Soghomonyan Hayk, Presl Robert, Ray Pabitro, Wieser Andreas, Keller Ursula, Phillips Christopher R
Department of Physics, Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland.
Department of Civil, Environmental and Geomatic Engineering, Institute of Geodesy and Photogrammetry, ETH Zurich, 8093 Zurich, Switzerland.
ACS Photonics. 2025 Mar 21;12(4):1829-1839. doi: 10.1021/acsphotonics.4c02199. eCollection 2025 Apr 16.
Dual-comb ranging has emerged as an effective technology for long-distance metrology, providing absolute distance measurements with high speed, precision, and accuracy. Here, we demonstrate a dual-comb ranging method that utilizes a free-space transceiver unit, enabling dead-zone-free measurements and simultaneous ranging with interchanged comb roles to allow for long-distance measurements, even when the target is moving. It includes a graphics processing unit (GPU)-accelerated algorithm for real-time signal processing and a free-running single-cavity solid-state dual-comb laser with a carrier wavelength λ ≈ 1055 nm, a pulse repetition rate of 1 GHz, and a repetition rate difference of 5.06 kHz. This combination offers a fast update rate and sufficient signal strength to reach a single-shot time-of-flight precision of around 0.1 μm (i.e., <λ/4) on a cooperative target placed at a distance of more than 40 m. The free-running laser is sufficiently stable to use the phase information for interferometric distance measurements, which improves the single-shot precision to <20 nm. To assess the ranging accuracy, we track the motion of the cooperative target when moved over 40 m and compare it to a reference interferometer. The residuals between the two measurements are below 3 μm. These results highlight the potential of this approach for accurate and dead-zone-free long-distance ranging, supporting real-time tracking with nm-level precision.
双梳测距已成为一种用于长距离计量的有效技术，可提供高速、高精度和高准确度的绝对距离测量。在此，我们展示了一种双梳测距方法，该方法利用自由空间收发单元，实现无死区测量以及在梳状信号角色互换时的同时测距，即使目标在移动也能进行长距离测量。它包括一种用于实时信号处理的图形处理单元（GPU）加速算法，以及一个自由运行的单腔固态双梳激光器，其载波波长λ≈1055nm，脉冲重复频率为1GHz，重复频率差为5.06kHz。这种组合提供了快速更新速率和足够的信号强度，在距离超过40m的合作目标上实现了约0.1μm（即<λ/4）的单次飞行时间精度。自由运行的激光器足够稳定，可将相位信息用于干涉式距离测量，从而将单次精度提高到<20nm。为了评估测距精度，我们跟踪合作目标在40m范围内移动时的运动，并将其与参考干涉仪进行比较。两次测量之间的残差低于3μm。这些结果突出了这种方法在精确和无死区长距离测距方面的潜力，支持纳米级精度的实时跟踪。
