The pseudogap and the unusual excitations in the optical conductivity of Bi2Sr2CaCu2O8+δ material

•In the underdoped to optimally doped regime, the pseudogap is observed in the optical conductivity spectra.•In the overdoped regime the pseudogap disappears and the optical conductivity behaves almost like the Drude conductivity.•In the overdoped regime, the trends like the cross-over region and the pseudogap signature in the optical conductivity were recover by this model.•The optical conductivity in the normal state is dominated by pseudogap and in the superconducting state it is dominated by unusual excitation.