RADIATIVE DECAY OF COLLECTIVE EXCITATIONS IN AN ARRAY OF QUANTUM DOTS

The problem of electromagnetic response and collective excitations in an array of quantum dots is solved in the self-consistent-held approxi mation using the complete system of Maxwell equations. We calculate th e radiative decay of collective excitations in the system and show tha t it can be of the order of or larger than the damping due to collisio ns. We show that in previous theoretical work the effect of radiation of electromagnetic waves by the dipole collective modes of the system was underestimated by several orders of magnitude. Our results remove the discrepancy between the observed and calculated linewidths of coll ective modes in arrays of dots. The results are discussed in connectio n with the related problem of the optical,properties of small polariza ble particles.