  We present optical nanoantennas designed for applications that require
processing temperatures larger than 800{\deg}C. The antennas consist of arrays
of Re/Pt bilayer strips fabricated with a lift-off-free technique on top of
etched trenches. Reflectance measurements show a clear plasmonic resonance at
approximately 670 nm for light polarized orthogonal to the strip axis. The
functionality of the antennas is demonstrated by growing single-walled carbon
nanotubes (CNTs) on top of the antenna arrays and measuring the corresponding
Raman signal enhancement of individual CNTs. The results of the measurements
are quantitatively discussed in light of numerical simulations which highlight
the impact of the substrate.
