Use of a Holographic Rejection Filter to Improve the Sensitivity of a Commercial Raman Microprobe

Publisher： Society for Applied Spectroscopy

ISSN： 0003-7028

Source： Applied Spectroscopy, Vol.46, Iss.5, 1992-05, pp. : 746-748

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Abstract

The use of a holographic rejection filter has been demonstrated to improve the sensitivity of a commercial Raman microprobe by a factor of ∼3.5, allowing shorter data accumulation times or a reduction of the laser intensity at the sample. The filter has been tested with two very different solid samples; the first (TiO₂ powder) gives a strong diffusely scattered laser beam along with the Raman scatter. The second (silicon) gives a strong specular reflection of the laser beam, again severely testing the laser rejection capabilities of the filter. Bands down to 200 cm⁻¹ shift were transmitted by the filter without attenuation but with satisfactory rejection of the laser line. This approach provides a simple way of enhancing the performance of a commercial microprobe at low cost.