Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System, Ministry of Education, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.
Jinan Institute of Quantum Technology, Jinan 250101, China.
Sensors (Basel). 2023 Jan 8;23(2):715. doi: 10.3390/s23020715.
We propose and implement a terahertz time-of-flight ranging system based on adaptive clock asynchronous optical sampling, where the timing jitter is corrected in real time to recover the depth information in the acquired interferograms after compensating for laser instabilities using electronic signal processing. Consequently, the involved measurement uncertainties caused by the timing jitter during the terahertz sampling process and the noise intensity of the terahertz electric field have been reduced by the utilization of the adaptive clock. The achieved uncertainty range is about 2.5 μm at a 5 cm distance after averaging the acquisition time of 1876 ms 5000 times, showing a significant improvement compared with the asynchronous optical sampling using a constant clock. The implemented terahertz ranging system only uses free-running mode-locked lasers without any phase-locked electronics, and this favors simple and robust operations for subsequent applications that extend beyond the laboratory conditions.
我们提出并实现了一种基于自适应时钟异步光采样的太赫兹飞行时间测距系统，其中实时校正定时抖动，在使用电子信号处理补偿激光不稳定后，恢复采集干涉图中的深度信息。因此，通过使用自适应时钟，减少了太赫兹采样过程中定时抖动和太赫兹电场噪声强度引起的测量不确定度。在平均 5000 次 1876 毫秒的采集时间后，在 5 厘米的距离处，实现的不确定度范围约为 2.5 μm，与使用固定时钟的异步光采样相比，有显著的改善。所实现的太赫兹测距系统仅使用自由运行锁模激光器，而不使用任何锁相电子设备，这有利于后续应用的简单和稳健操作，这些应用超出了实验室条件。
