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On-chip, self-detected THz dual-comb spectrometer (1602.00537v1)
Published 1 Feb 2016 in physics.optics
Abstract: We present a directly generated on-chip dual-comb source at THz frequencies. The multi-heterodyne beating signal of two free-running THz quantum cascade laser frequency combs is measured electrically using one of the combs as a detector, fully exploiting the unique characteristics of quantum cascade active regions. Up to 30 modes can be detected corresponding to a spectral bandwidth of 630 GHz, being the available bandwidth of the dual comb configuration. The multi-heterodyne signal is used to investigate the equidistance of the comb modes showing an accuracy of $10{-12}$ at the carrier frequency of 2.5 THz.