Precision molecular spectroscopy with a phase-locked terahertz quantum-cascade laser
Journal article, 2025
We demonstrate precision molecular spectroscopy with a phase-locked quantum cascade laser (QCL) over its entire frequency tuning range at 3.4 THz. A Schottky diode harmonic mixer is used to mix the QCL emission with a multiplied microwave signal, referenced to a rubidium frequency standard, to create an intermediate frequency (IF) signal, which is used to phase-lock the QCL. Tuning the frequency of the multiplied microwave reference and keeping the IF fixed allows for precise frequency control of the laser. We identify ten methanol transitions between 3443.5 and 3447.6 GHz and quantify the transition frequencies and broadening parameters with high precision. These measurements are performed without liquid cryogens in a compact setup.
Author
Robert Voigt
Humboldt University of Berlin
German Aerospace Center (DLR)
Martin Wienold
German Aerospace Center (DLR)
Divya Jayasankar
Chalmers, Microtechnology and Nanoscience (MC2), Terahertz and Millimetre Wave Laboratory
Jan Stake
Chalmers, Microtechnology and Nanoscience (MC2), Terahertz and Millimetre Wave Laboratory
Xiang Lü
Paul Drude Institut fur Festkorperelektronik
Klaus Biermann
Paul Drude Institut fur Festkorperelektronik
Heinz-Wilhelm Hübers
German Aerospace Center (DLR)
Humboldt University of Berlin
Optics Express
1094-4087 (ISSN) 10944087 (eISSN)
Vol. 33 7 15782-15788Supraterahertzelektronik för framtida FIR instrument
Swedish National Space Board (2023-00310), 2024-01-01 -- 2027-12-31.
Infrastructure
Kollberg Laboratory
Areas of Advance
Nanoscience and Nanotechnology
Subject Categories (SSIF 2025)
Electrical Engineering, Electronic Engineering, Information Engineering
DOI
10.1364/OE.553739