title: Theory of intrinsic linewidth based on fluctuation-dissipation balance for thermal photons in THz quantum-cascade lasers.
abstract: 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.
authors.affiliation: Central Research Laboratories, Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamakitaku, Hamamatsu 434-8601 Japan. masamiya@crl.hpk.co.jp
authors.forename: Masamichi
authors.initials: M
authors.lastname: Yamanishi
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004735:Energy Transfer; D007834:Lasers; D008962:Models, Theoretical; D011789:Quantum Theory; D012031:Refractometry / Q000379:methods*; D012542:Scattering, Radiation; D055053:Terahertz Radiation