  A commercial single laser line Raman spectrometer is modified to accommodate
multiline and tunable dye lasers, thus combining the high sensitivity of such
single monochromator systems with broadband operation. Such instruments rely on
high-throughput interference filters that perform both beam alignment and
Rayleigh filtering. Our setup separates the dual task of the built-in
monochromator into two independent elements: a beam splitter and a long pass
filter. Filter rotation shifts the transmission passband, effectively expanding
the range of operation. Rotation of the filters has a negligible effect on the
optical path, allowing broadband operation and stray light rejection down to
70-150 1/cm. Operation is demonstrated on single-walled carbon nanotubes, for
which the setup was optimized.
