Optical bandgap and dispersions of 0.24Pb(In1/2Nb1/2)O3-0.43Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 single crystal poled along [011]c direction

•The temperature dependence of the optical direction energy bandgaps were calculated.•The parameters in Varshni equation were obtained.•The parameters of room temperature monomial Sellmeier oscillator were derived.

The ternary relaxor-based ferroelectric single crystal 0.24Pb(In1/2Nb1/2)O3-0.43Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 (0.24PIN-0.43PMN-0.33 PT) poled along [011]c has single domain state and remarkable optical properties. The temperature dependence of the optical direction energy bandgap for the single crystal coincides with dielectric constant curve at the phase transition points. The variation tendency of the bandgap energies in different phase structures coincide with Varshni equation. The parameters in Varshni equation were obtained from the approximate fitting of the optical bandgap energies, which were calculated at various temperatures from 300 to 540 K. The refractive indices and the extinction coefficients in the single-domain state were obtained. The parameters of room temperature monomial Sellmeier oscillator were also derived.