Adaptation of a commercial Raman spectrometer for multiline and broadband laser operation

TL;DR

This paper describes how a commercial Raman spectrometer was modified with a dual-filter system to enable multiline and broadband laser operation, enhancing its versatility for various spectroscopic applications.

Contribution

The authors developed a modified Raman spectrometer that separates beam alignment and filtering, allowing broadband operation without significant optical path disturbance.

Findings

Successful broadband operation demonstrated on carbon nanotubes

Stray light rejection achieved down to 70-150 1/cm

Enhanced versatility of Raman spectrometers for multiline lasers

Abstract

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.