The Billiard Ball Model, the Elliptical Billiard Ball Model, and Angled-Beam Photon Echoes.

The Billiard Ball model is developed as a new way of visualizing many coherent transient phenomena. Several different aspects of the photon echo formation process are explained using this model and its extension, the Elliptical Billiard Ball model. The results of a series of experiments that verify some of the predictions of these models are presented. We observed in some of these experiments a dynamic range of nearly 12 orders of magnitude; it should be possible to observe echo intensities over even larger dynamic ranges.