Laser dressing of the electronic bands in semiconductors

We discuss the validity of the renormalized effective mass approximation to treat the interaction of a laser field with a semiconductor, in a one-body approximation. The electronic band structure of the semiconductor is modeled by two-parabolic, isotropic bands in the k→·p→ approximation. To incorporate the laser field into an effective mass formalism (renormalized effective mass approximation) we apply the dressed-atom approach to the two-band model (dressed-band approximation), the eigenvalue problem for the dressed bands is solved analytically and a k expansion is performed. The validity of the renormalized mass approximation is studied, comparing the results for the quasi-energy spectrum and for the effective mass obtained from the renormalized mass approximation, the dressed-band approximation and the “exact” results derived from the diagonalization of the Floquet matrix. We show that for the laser intensities which will not damage the semiconductor samples in experiments, the agreement is excellent.