Large Petermann factor in chaotic cavities with many scattering channels
Laboratoire de Physique Quantique, UMR 5626 du CNRS,
Université Paul Sabatier F-31062 Toulouse Cedex 4, France
2 Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506 2300 RA Leiden, The Netherlands
Accepted: 26 October 1999
The quantum-limited linewidth of a laser cavity is enhanced above the Schawlow-Townes value by the Petermann factor K, due to the non-orthogonality of the cavity modes. The average Petermann factor in an ensemble of cavities with chaotic scattering and broken time-reversal symmetry is calculated non-perturbatively using random-matrix theory and the supersymmetry technique, as a function of the decay rate Γ of the lasing mode and the number of scattering channels N. We find for that for typical values of Γ the average Petermann factor is parametrically larger than unity.
PACS: 42.50.Lc – Quantum fluctuations, quantum noise, and quantum jumps / 42.50.Ar – Photon statistics and coherence theory / 42.60.Da – Resonators, cavities, amplifiers, arrays, and rings
© EDP Sciences, 2000