The optical response of doubly charged sodium clusters Nan+2++ was measured for n = 20, 40, and 58 valence electrons, for which the jellium model predicts spherical clusters. A new experimental scheme was developed which allows to separate doubly charged clusters of even mass from the singly charged with half the mass. The optical spectra are dominated by a plasmon-like resonance which is blue shifted and narrower than that of the singly charged clusters. The smallest doubly charged cluster observed was Na9++. The photo ionization cross section for singly charged clusters was found to be typically 2.6·10-19cm2 per Na atom for photon energies of around 6 eV, which is a factor of 400 smaller than the maximum in the plasmon absorption in the region of hω=2.6 eV.