2016 Volume 85 Issue 2 Pages 123-126
Real-time measurement of the absolute frequency of continuous-wave terahertz (CW-THz) radiation is required for the characterization and frequency calibration of practical CW-THz sources. We proposed a method for real-time monitoring of the absolute frequency of CW-THz radiation based on dual THz frequency combs of photocarriers (PC-THz combs) with different frequency spacings. Regardless of the absence of frequency controls in the PC-THz combs, a frequency precision of 10-11 was achieved at a measurement rate of 100 Hz. Furthermore, large fluctuations of the CW-THz frequencies, crossing a few modes of the PC-THz combs, was correctly monitored in real time. The proposed method will be a powerful tool for the research and development of practical CW-THz sources, and other applications.
