Relative Intensity Noise Characterization of a Quantum Cascade Laser Frequency-Comb Symmetric Dual-Comb Spectrometer

We measure the relative intensity noise (RIN) of a symmetric Dual-Comb Spectrometer enabled by quantum cascade laser frequency-combs. The RIN of the maximum peak in the multiheterodyne spectra is mitigated from 5.2 ∗ 10 − 3 Hz − 1 2 to 2.2 ∗ 10 − 3 H z − 1 2 by performing digitally balanced detection between signal and reference channels.