Synthetized Terahertz Frequency Combs

Nowadays, frequency combs (FCs) are regarded as state-of-the-art measurement tools, when it comes to high precision experiments. Among the various possibilities to generate FCs, techniques based on electro-optic (EO) modulation provide the advantage of great freedom in the FC shaping process. Therefore, tunable FC sources utilizing EO modulators find application in numerous research fields including interferometry, metrology and spectroscopy [1] . So far, EO FCs are mainly restricted to the near-infrared (NIR) spectral region, since the realization of EO modulators for the mid-infrared (MIR) and Terahertz (THz) domain is a challenging task. These limitations can be overcome, when NIR EO FCs are converted into the desired wavelength range by a nonlinear frequency conversion process [2] . Especially spectroscopic applications in the MIR and THz benefit, when EO FCs can be used to target the many rotational and vibrational transitions lying in these parts of the electromagnetic spectrum.