“…The linear theory of the polariton modes has been developed [2] (chap. 4), [9,10], and validated experimentally [11,12], it involves many complications due to finite-size effects. On the other hand, the study of solitary waves, or singleoscillation waves, which is fundamental for soliton theory from both the water wave and the mathematical viewpoints [13], is now a fast-growing field in nonlinear optics.…”