Résumé
The negative shifts seen by
Wang
and
Zhu
[
Appl. Phys. Lett.
87
,
221102
(
2005
)
] are not due to the excitation of surface plasmons but to leaky modes of the slab propagating backward. Provided the characteristics of the left-handed material slab are chosen correctly, it is shown that a leaky surface plasmon can actually be excited using the Kretschmann-Raether configuration.