光全息制作的变形面心立方结构光子晶体的带隙

四束激光从空气直接入射到平面结构的感光树脂所制备的面心立方结构实际上是一种不但晶格沿[111]方向拉伸,而且其格点也在[111]方向被拉长的变形面心立方结构。在对这种变形面心立方结构的光子晶体的晶格形状及能带分布的研究中,通过利用麻省理工学院的光子晶体能带计算程序计算了各种参量对此变形面心立方结构的蛋白石和反蛋白石的能带分布的影响,发现在一定条件下该结构的蛋白石会出现完全光子带隙。用激光全息聚合法在正胶的环氧树脂中可制作反蛋白石模板,若用此模板制作硅蛋白石,当晶格沿[111]方向拉伸2.1倍和硅的占空比为13.7%时出现最大的带隙宽度。此最大带隙宽度的结构的制作光路是三角锥形光路,对称地环绕中央光束的三束外围激光束之间夹角为54.0°,三束外围激光束与中央激光束夹角为31.6°。

Photonic Band Gap of the Distorted Face-Center-Cubic Structure Photonic Crystal Fabricated by Holographic Lithography

The face-center-cubic structure obtained by four incident laser beams directly from air to photoresist of planar construction, is actually a kind of distorted face-center-cubic structure. Both of its lattices and its latticesites are lengthened along [111] direction. In the study on the lattice shape and band structure of this distorted face-center-cubic structure, using MIT's Photonic-Bands program, after calculating the relations between the energy band structure and all kinds of parameters of opal and inverse opal, a complete photonic band-gap in its opal structure is obtained. The largest photonic band-gap is obtained as the lengthening ratio is 2.1 and the filling ratio of silica is 13.7%. For fabrication of this structure with largest photonic band-gap by holographic lithography method, which needs two steps (fabrication of opal and fabrication of inverse opal by filling), the three outer beams are placed symmetrically around the central beam, the three outer beams are 54.0° apart, and the angles between the central beam and outer beams are 31.6°.