Two-photon absorption in direct-gap crystals—an addendum

Abstract
An error made in an earlier paper by the authors regarding the appropriate effective masses to be used in calculations employing the Basov formulation is corrected. The new results for two-photon absorption coefficient obtained from the Basov formula now agree quite well with those computed using Keldysh's treatment. Furthermore, it is shown that improved agreement between theoretical and experimental two-photon absorption coefficients is obtained by including nonparabolicity and degeneracy of the energy bands in the calculations.