Experimental estimate of the nonlinear refractive index of crystalline ZnSe in the terahertz spectral range
A. N. Tcypkin, S. E. Putilin, M. C. Kulya, M. V. Melnik, A. A. Drozdov, V. G. Bespalov, X.-C. Zhang, R. W. Boyd, and S. A. Kozlov, Bull. Russ. Acad. Sci. Phys. 82, 1547–1549 (2018).