Theory for photon statistics of random lasers

A theory for the photon statistics of a random laser is presented. Noise is described by Langevin terms, where fluctuations of both the electromagnetic field and of the medium are included. The theory is valid for all lasers with small outcoupling when the laser cavity is large compared to the wavelength of the radiation. The theory is applied to a chaotic laser cavity with a small opening. It is known that a large number of modes can be above threshold simultaneously in such a cavity. It is shown that the amount of fluctuations is increased above the Poissonian value by an amount that depends on the number of modes above threshold.