INTERSUBBAND OPTICAL-ABSORPTION IN SEMICONDUCTOR SUPERLATTICES WITH COMPLEX BASES

The third-order nonlinear intersubband optical absorption coefficient within the conduction band of semiconductor superlattices with complex bases have been calculated using the density matrix formalism includi ng intrasubband and intersubband relaxation. The subband dipole moment s z(ij)(k) and z(ii)(k) are first studied in superlattices with comple x 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 fu nctions of and strongly depends on the well parameters. The intersubba nd transition optical absorption coefficient alpha(omega, I) is furthe r studied. The numerical illustrations are also given.