Optical Dispersion Relations The Reststrahlen Region The Interband Transition Region Model Dielectric Function (a) E0 and E0 + Δ0 Transitions (b) E1 and E1 + Δ1 Transitions (c) E′0 (E2)Transitions (d) Indirect-Band-Gap Transitions (e) Excitons and Exciton Parameters Experimental ϵ1 and ϵ2 Spectra Dispersion of the Refractive-Index, Extinction, and Absorption Coefficients Free-Carrier Effects on Optical Properties Optical Absorption Carrier-Induced Change in Refractive Index Intervalence-Band Absorption Nonlinear Index of Refraction and Absorption References