Fig. 1. Schematic of the THz QCL dual-comb experimental setup

Fig. 2. Terahertz spectra of the polarizer measured when the rotation angle is varied from 0 to 90°in a frequency range between 1.5 and 12 THz. The spectrum with highest intensities is the background signal which was obtained without the polarizer

Fig. 3. Polarization angle dependence of the measured transmission of the polarizer in polar coordinates

Fig. 4. Repetition frequencies of Comb1 and Comb2 measured with a polarization angle of 0°

Fig. 5. Dual-comb spectra measured at 0°，20°，40°，60° polarization angles

Fig. 6. Dual-comb signal power in polar coordinates as a function of polarization angle