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Updated: Feb 15, 2026

Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
Absolute spectroscopy near 7.8 μm with a comb-locked extended-cavity quantum-cascade-laser
Marco Lamperti1, Bidoor AlSaif2, Davide Gatti1
1Physics Department of Politecnico di Milano and IFN-CNR, Via G. Previati 1/C, 23900, Lecco, Italy.
Abstract:
We report for the first time the frequency locking of an extended-cavity quantum-cascade-laser (EC-QCL) to a near-infrared frequency comb. The locked laser source is exploited to carry out molecular spectroscopy around 7.8 μm with a line-centre frequency combined uncertainty of ~63 kHz. The strength of the approach, in view of an accurate retrieval of line centre frequencies over a spectral range as large as 100 cm-1, is demonstrated on the P(40), P(18) and R(31) lines of the fundamental rovibrational band of N2O covering the centre and edges of the P and R branches. The spectrometer has the potential to be straightforwardly extended to other spectral ranges, till 12 μm, which is the current wavelength limit for commercial cw EC-QCLs.
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