INTERSUBBAND OPTICAL ABSORPTION IN SEMICONDUCTOR SUPERLATTICES WITH COMPLEX BASES

The third-order nonlinear intersubband optical absorption coefficient within the con-duction band of semiconductor superlattices with complex bases have been calculated using the density matrix formalism including intrasubband and intersubband relaxation. The sub-band dipole moments z_ij(k) and z_ii(k) are first studied in superlattices with complex bases including a general coupled-well basis and a general step-well basis. The results show that z_ij(k) and z_ii(k) are complicated functions of and strongly depends on the well parameters. The intersubband transition optical absorption coefficient \alpha(\omega, I) is further studied. The numerical illustrations are also given.