Approximate approach to the quantum statistics of the superposition of coherent and chaotic fields

Formulae recently derived for the integrated intensity distribution, the photon-counting distribution and its factorial moments in the statistics of the superposition of multimode coherent and chaotic fields are analyzed in greater detail and their validity as approximate formulae for light of arbitrary spectrum is investigated. It is shown by explicit calculation of the third factorial moment of the photon-counting distribution for the superposition of a one-mode coherent field with a Gaussian Lorentzian field that the proposed formulae hold with very good accuracy over a wide range of conditions.The authors thank Dr. Z. Braunerová and M T. Kojecký of the Computer Center of Palacký University for their help with calculations.