Quasinormal modes in two-photon autocorrelation and the geometric-optics approximation Wei-Liang Qian, Kai Lin, Xiao-Mei Kuang, Bin Wang and Rui-Hong Yue Eur. Phys. J. C, 82 3 (2022) 188 Published online: 01 March 2022 DOI: 10.1140/epjc/s10052-022-10155-w