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Photonic crystals (PC) also known as photonic band gap materials has brought a new revolution in nano photonics. They are highly promising for fabricating ultra fast devices. This field is relatively new and mostly in the way of research and development for exploiting novel properties. PCs are composed of periodic dielectric or metallo-dielelectric (nano) structured that are designed to affet thepropagation of electromagnetic (EM) waves in the same as the periodic potential in a semiconductor. The absence of allowed propagation EM modes inside the structures, in a range of wave length called photonic band gap(PBG), gives rise to distinct optical phenomena such as inhibition of spontaneous emission, high-loss-wave guiding amongst others. This review introduces PBG materials that concieved to control the propagation of EM waves.

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Abebe Demoz, Msc: Studied solid state physics at Addis Ababa University. Lecturer at Gondar College of Teacher education, Ethiopia.

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