Yv. Rostovtsev et al., ELECTROMAGNETIC-INDUCED TRANSPARENCY AND AMPLIFICATION OF ELECTROMAGNETIC-WAVES IN PHOTONIC BAND-GAP MATERIALS, Physical review. A, 57(6), 1998, pp. 4919-4924
We investigate the propagation of an electromagnetic (EM) wave in a he
terostructure formed by spatially modulated density of Lambda three-le
vel atoms. A new regime of propagation and amplification of EM waves w
ith frequencies lying in the forbidden frequency range is found. An ap
plication of this phenomenon is discussed.