Broadening of effective photonic band gaps in biological chiral structures: From intrinsic narrow band gaps to broad band reflection spectraW. E. Vargas, M. Hernández-Jiménez, E. Libby, D. E. Azofeifa, Á. Solis and C. Barboza-AguilarEPL, 111 6 (2015) 64001DOI: https://doi.org/10.1209/0295-5075/111/64001