Mesoscopic cooperative emission from a disordered system

We study theoretically the cooperative light emission from a system of N»1 classical oscillators confined within a volume with spatial scale L much smaller than the radiation wavelength λο=2rrc/ω0. We assume that the oscillator frequencies are randomly distributed around a central frequency ωο with some characteristic width Ω«ω0. In the absence of disorder, that is, Ω=0, the cooperative emission spectrum is composed of a narrow subradiant peak superimposed on a wide superradiant band. When Ω≠o, we demonstrate that if N is large enough, the subradiant peak is not simply broadened by the disorder but rather splits into a system of random narrow peaks. We estimate the spectral width of these peaks as a function of N, L, Ω, and λο. We also estimate the amplitude of this mesoscopic structure in the emission spectrum.