Internal transitions in the confined biexciton

Optical internal transitions relevant to experiments based on the optical d etection of far-infrared resonances are computed for the biexciton in a qua ntum dot in the strong-confinement regime. Valence sub-band-mixing effects are taken into account in second-order perturbation theory. The probability of transition from the ground state is concentrated in a few states with r elatively high excitation energies. Level collisions with oscillator streng th transfer are observed as the magnetic field is raised.