Quantum-limited linewidth in THz quantum cascade lasers
Authors: Vitiello M.S., Consolino L., Bartalini S., Taschin A., Tredicucci A., Inguscio M., De Natale P.
Autors Affiliation: CNR- Istituto Nazionale di Ottica and LENS (European Laboratory for Non-linear Spectroscopy), Via Carrara 1, 50019 Sesto Fiorentino (FI), Italy; NEST, CNR – Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa, I-56127, Italy; Dipartimento di Fisica e Astronomia, Università Degli Studi di Firenze, Via Carrara 1, 50019 Sesto Fiorentino(FI), Italy
Abstract: Quantum cascade lasers (QCLs) are powerful testing grounds for the fundamental physical parameters determined by their quantum nature. The associated wealth of unique physical properties makes the QCL a subject of extensive research, especially across the far-infrared, where the electron-phonon relaxation dynamics, the gain mechanisms and the related intrinsic QCL features need to be extensively investigated. Here, we report a complete overview of the frequency-noise power spectral density of a THz QCL, giving an experimental and analytical evaluation of its intrinsic linewidth and a full investigation of the physics beyond it, offering a new perspective of use of ultra-narrow THz QCL sources as a metrological grade tool for a widespread range of photonic applications.
KeyWords: Analytical evaluation; Electron-phonon relaxation; Frequency metrology; Photonic application; Physical parameters; Quantum cascade lasers (QCLs); Terahertz photonics; THz quantum cascade lasers, Power spectral density; Quantum cascade lasers, NanophotonicsDOI: 10.1117/12.2006029