Light propagation through a single gain layer and a multilayer system with gain layers is studied. Results obtained using the Fresnel formulas, Airy’s series summation, and the numerical solution of the nonlinear Maxwell—Bloch equations by the finite difference time domain (FDTD) method are analyzed and compared. Normal and oblique propagation of a wave through a gain layer and a slab of a photonic crystal are examined. For the latter problem, the gain line may be situated in either the pass or stop band of the photonic crystal. It is shown that the monochromatic plane-wave approximation is generally inapplicable for active media, because it leads to results that violate causality. But the problem becomes physically meaningful and correct results can be obtained for all three approaches once the structure of the wavefront and the finite aperture of the beam are taken into account.

PACS: 41.20.Jb, 42.70.Qs, 73.20.−r (all) DOI: 10.3367/UFNe.0182.201211b.1157 URL: https://ufn.ru/en/articles/2012/11/b/ 000314808600002 2-s2.0-84873896836 2012PhyU...55.1080D Citation: Dorofeenko A V, Zyablovsky A A, Pukhov A A, Lisyansky A A, Vinogradov A P "Light propagation in composite materials with gain layers" Phys. Usp. 55 1080–1097 (2012) BibTexBibNote ® (generic)BibNote ® (RIS)MedlineRefWorks Received: 27th, October 2010, revised: 16th, July 2012, accepted: 2nd, August 2012 Оригинал: Дорофеенко А В, Зябловский А А, Пухов А А, Лисянский А А, Виноградов А П «Прохождение света через композитные материалы, содержащие усиливающие слои» УФН 182 1157–1175 (2012); DOI: 10.3367/UFNr.0182.201211b.1157