The refractive index of a material describes the behavior of light propagating through it (Fig. ). The static refractive index ( (0)), the value of the refractive index at zero energy is 1.08 and 1.29 for in-plane and out-of-plane direction which is higher than h-BN. However, the highest value of the refractive index is 1.60 (at 12.55 eV) and 1.77 (at 11.67 eV) for FBNF in in-plane and out-of-plane directions. The findings of the optical calculation (Table ) are very consistent with the available literature .