Quantum noise in intracavity laser spectroscopy

The limitations on the intracavity laser spectroscopy (ILS) method are considered which are caused by the statistical character of the multimode laser radiation. Stochastic processes (shot photon noise) are shown to result in a heavily “jagged” function, instead of a smooth one, which describes a specific realization of the generation spectrum. The increase of fluctuations with time between two successive measurements of the spectrum has also been investigated. The threshold sensitivity for the ILS method has been found which is determined by the stochastic character of the multimode generation.