  We measured polarization-dependent photoluminescence-excitation spectra of
highly uniform T-shaped quantum wires at 5 K. We attribute one peak to the
1D-exciton ground state and the continuous absorption band to 1D continuum
states. These had similar polarization-dependences. We also observed some other
peaks above the 1D-exciton ground state and attribute them to exciton states
consisting of excited hole subbands. These results show good agreement with a
model calculation of a single electron-hole pair in T-shaped geometry with
exact diagonalizations of the Coulomb interaction.
