含负折射率介质光子晶体的斜角禁带

研究了由正负折射率介质交替排列构成的光子晶体的传输特性,负折射率材料(NIM)是有损耗的Drude色散媒质。研究发现,这类光子晶体具有零折射率带和传统的Bragg带,此外在NIM的折射率接近于零的频域还出现了一个新型的禁带——斜角带。该斜角带的位置与晶格参数无关,其带宽较小;在电磁波垂直入射时禁带消失,但随着入射角的增大禁带逐渐展宽,且TM模的带宽大于TE模。

An unusual angular gap of 1-D photonic crystal containing negative refractive index materials

It is studied the transmission properties of the photonic crystal alternatively composed of material layers with positive and negative index,where the negative index materials(NIM) is described by a lossy Drude model.Investigations reveal that such structure possesses zero-n Bragg gap and conventional Bragg gaps.In additional,there is a new type of band gap emerged in the spectral region where the refractive index of NlM is approximately zero.The position of this so-called angular gap has no relation to crystal parameters,and the band width is quite small.The forbidden band disappears at normal incidence,the width of the angular gap increases while increasing the incidence angle,and the width of TM is larger than that of TE.