Nature of the superluminescence of organic crystals

A theoretical analysis is made of the kinetics of the luminescence emitted by organic crystals. It is shown that when the excitation rate is increased, the luminescence may be influenced strongly by phonons generated as a result of exciton annihilation which produces photons. Superluminescence may appear because of the generation of a coherent vibration field, accompanied by phonon emission. Feedback in the vibration field is due to reflections from the boundaries of a crystal. Estimates are obtained of the conditions for the self-excitation of the phonon field in anthracene crystal.