The effect of dissipation in a Kerr medium on the error of wave energy measurements

In quasi-nonperturbing measurements of wave energy, dissipation due to wave interaction in a Kerr medium is shown to restrict the error of determining the number $N$ of quanta to a value of $\sqrt{Nq}$ ($q$ is the absorption coefficient). Self-action of the wave and its dissipation determine the optimum power of the probing wave and the interaction length.