基于六边形基元的光子晶体宽带大角度自准直特性研究

Wide-band large-angle self-collimation in photonic crystal with trapezoid bases

通过对能带结构和等频图(EFC)的分析,提出的基于六边形基元的正方点阵光子晶体结构(PR-PC)具有宽带大角度自准直特性.宽带自准直频率范围达1.47 GHz,相对中心频率带宽为11.85﹪,入射角范围可以超过±45°.长径比变大情况下,最终出现全角度自准直.数值结果表明:通过改变填充因子、长径比可以实现对PR-PC结构的自准直频率范围、中心频率值以及入射角范围的调整.

The two dimensional trapezoid -shaped photonic crystal （PC） （PR -PC） was investigated in or- der to succeed self - collimation over a broad bandwidth by analyzing the band structure and equi - frequency - contour （ EFC ）. The proposed structure supports a self - collimation effect over a broad frequency range of 1.47 GHz with a bandwidth 11.85 %. Incident self - collimation angle range can be more than ±45°. Eventually, along with the length to diameter ratio, angle range can be in the whole angular range of ±90°. The numerical results show that self - collimation frequency range, center frequency and incident angle range can be adjusted by changing the fill factor, the length to diameter ratio.