  Earlier apodized-pupil Lyot coronagraphs (APLC) have been studied and
developed to enable high-contrast imaging for exoplanet detection and
characterization with present-day ground-based telescopes. With the current
interest in the development of the next generation of telescopes, the future
extremely large telescopes (ELTs), alternative APLC designs involving
multistage configuration appear attractive. The interest of these designs for
application to ELTs is studied. Performance and sensitivity of multistage APLC
to ELT specificities are analyzed and discussed, taking into account several
ineluctable coronagraphic telescope error sources by means of numerical
simulations. Additionally, a first laboratory experiment with a two-stages-APLC
in the near-infrared (H-band) is presented to further support the numerical
treatment. Multistage configurations are found to be inappropriate to ELTs. The
theoretical gain offered by a multistage design over the classical single-stage
APLC is largely compromised by the presence of inherent error sources occurring
in a coronagraphic telescope, and in particular in ELTs. The APLC remains an
attractive solution for ELTs, but rather in its conventional single-stage
configuration.
