Soviet Journal of Quantum Electronics
Theory of parametric scattering and method of absolute measurement of the brightness of light
G. Kh. Kitaeva, Давид Николаевич Клышко, I V Taubin
Abstract
An investigation is made of the feasibility of absolute measurements of the brightness of light from the signal-to-noise ratio M of a parametric frequency converter with reflection and absorption in a nonlinear crystal. A model of a plane-parallel layer and a constant monochromatic pump source of frequency ω 0 is used. Equations are derived to describe the transmission and reflection of waves with frequencies ω 1 and ω 2 = ω 0 – ω 1 in the layer. The resultant four-dimensional scattering matrix determines the quantum noise of the converter in accordance with the "nonlinear" Kirchhoff law. It is found that the number of photons per mode N in the incident light is equal to M multiplied by a correction factor close to unity, which depends on the absorption coefficient and on the refractive index.