Six-fold hybrid photonic crystal formed holographically with full band gap for low refractive indexG.-Y. Dong, X.-L. Yang, L.-Z. Cai, X.-X. Shen, X.-F. Meng, X.-F. Xu and H. ZhangEPL, 80 1 (2007) 14006DOI: https://doi.org/10.1209/0295-5075/80/14006