  BiFeO$_{3}$ is multiferroic material with space group Pbnm exhibits coupling
of both magnetic and electric orders under strain force. To analyze band gap
Tauc plot extrapolation method is used $\&$ remarkably smaller than some
reported literature values for space group R3c structure. The dielectric
function $\varepsilon(\omega)$ demonstrated that light energy upon transition
through BiFeO$_{3}$ has shown a decline inconsistent pattern with index of
refraction variation in range of 13 to 8, 8 to 5, 5 to 3, $\&$ 3 to 1 as per
photon energy. Moreover, non crossing degenerate energy level and hybridized
spin-orbit interaction lead to linear dispersion relation which is typical
photonic nature with zero DM interaction. Thus, BiFeO$_{3}$ could exhibit
photonic property under strain force. Generally strained structure had enhanced
photovoltaic effect with smaller optical band gap because of
$Dzyaloshinskii$-$Moriya(DM)$ and spin-orbit coupling interactions.
