  Multiphoton ionization provides a clear window into the nature of electron
correlations in the helium atom. In the present study, the final state energy
range extends up to the region near the $N=2$ and $N=3$ ionization thresholds,
where two-photon ionization proceeds via continuum intermediate states above
the lowest threshold. Our calculations are performed using multichannel quantum
defect theory (MQDT) and the streamlined R-matrix method. The sum and
integration over all intermediate states in the two-photon ionization amplitude
is evaluated using the inhomogeneous R-matrix method developed by Robicheaux
and Gao. The seamless connection of that method with MQDT allows us to present
high resolution spectra of the final state Rydberg resonances. Our analysis
classifies the resonances above the $N=2$ threshold in terms of their group
theory quantum numbers. Their dominant decay channels are found to obey the
previously conjectured propensity rule far more weakly for these even parity
states than was observed for the odd-parity states relevant to single photon
ionization.
