Controlling and Phase-Locking a THz Quantum Cascade Laser Frequency Comb by Small Optical Frequency Tuning

Year: 2021

Authors: Consolino L., Campa A., De Regis M., Cappelli F., Scalari G., Faist J., Beck M., Rosch M., Bartalini S., De Natale P.

Autors Affiliation: CNR-INO National Institute of Optics and LENS, Via Nello Carrara 1, Sesto Fiorentino, Florence, I-50019, Italy; Institute for Quantum Electronics, ETH Zurich, Zurich, 8093, Institute for Quantum Electronics, ETH Zurich, Zurich, 8093, Switzerland

Abstract: Full phase control of terahertz (THz)-emitting quantum cascade laser (QCL) combs has recently been demonstrated, opening new perspectives for even the most demanding applications. In this framework, simplifying the set-ups for control of these devices will help to accelerate their spreading in many fields. This study reports a new way to control the emission frequencies of a THz QCL comb by small optical frequency tuning (SOFT), using a very simple experimental setup, exploiting the incoherent emission of an ordinary white light-emitting diode. The slightly perturbative regime accessible in these conditions allows tweaking the complex refractive index of the semiconductor without destabilizing the broadband laser gain. The SOFT actuator is characterized and compared to another actuator, the QCL driving current. The suitability of this additional degree of freedom for frequency and phase stabilization of a THz QCL comb is shown and perspectives are discussed.


Volume: 15 (6)      Pages from: 2000417-1  to: 2000417-8

More Information: The authors acknowledge the financial support from ERC grant CHIC (724344), the Qombs Project, EU-H2020-FET Flagship on Quantum Technologies grant no. 820419, the Italian ESFRI Roadmap (Extreme Light Infrastructure-ELI), EC-H2020 Laserlab-Europe grant agreement 654148, and the EC Project 665158 (ULTRAQCL).
KeyWords: frequency combs; quantum cascade lasers; terahertz optics
DOI: 10.1002/lpor.202000417