Ultra-deep stopband induced by spontaneous-emission-cancellation–like interference between two side-coupled zero-index-metamaterial–based resonatorsY. H. Li, Z. D. Dong, Y. Sun, W. Tan, H. T. Jiang, Z G. Wang and H. ChenEPL, 100 3 (2012) 34003DOI: https://doi.org/10.1209/0295-5075/100/34003