Absolute-Frequency high-resolution real-time terahertz dual-comb spectrometer

An absolute-frequency Terahertz dual frequency comb spectrometer for tunable, high-resolution and real-time rapid acquisition is presented. Two combs (probe and local oscillator) are electro-optically generated from the same line of a master optical frequency comb selected by optical injection locking. Photomixing each of these two initial optical combs with a coherent mode from the same master comb generates a narrow-linewidth Terahertz dual comb through difference frequency generation. The resulting dual-comb teeth are absolutely referenced to a RF clock standard.