Open AccessTheory of intrinsic linewidth based on fluctuation-dissipation balance for thermal photons in THz quantum-cascade lasers
Author(s) -
Masamichi Yamanishi
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.028465
Subject(s) - laser linewidth , photon , physics , optics , laser , dissipation , thermal , cascade , quantum cascade laser , photonics , optoelectronics , atomic physics , quantum mechanics , chemistry , chromatography , meteorology
Intrinsic linewidth formula modified by taking account of fluctuation-dissipation balance for thermal photons in a THz quantum-cascade laser (QCL) is exhibited. The linewidth formula based on the model that counts explicitly the influence of noisy stimulated emissions due to thermal photons existing inside the laser cavity interprets experimental results on intrinsic linewidth, ~91.1 Hz reported recently with a 2.5 THz bound-to-continuum QCL. The line-broadening induced by thermal photons is estimated to be ~22.4 Hz, i.e., 34% broadening. The modified linewidth formula is utilized as a bench mark in engineering of THz thermal photons inside laser cavities.