Shifted Wave Interference Fourier Transform Spectroscopy of Harmonic and Fundamental RF Injection-Locked THz Quantum Cascade Laser Frequency Combs

Shifted Wave Interference Fourier Transform Spectroscopy allows us to reveal the temporal intensity profiles of RF injection-locked fundamental and harmonic comb states of a broadband, multi-stack THz Quantum Cascade Laser. Depending on the injection power and frequency AM and FM modulated emission can be observed.