The development of handheld and portable Raman systems has brought a relatively unknown analytical technique into main stream applications.
Most of the portable and handheld applications today require high spectral resolution and a large sample interrogation area as most compounds and samples are heterogeneous. In addition, the tight laser focus increases the laser power density which creates localised heat buildup at the sample. This intense heat can damage the sample, which is observed on delicate Surface-Enhanced Raman Scattering (SERS) substrates or dark materials.
Metrohm has overcome this hurdle with the Orbital-Raster-Scan (ORS) sampling with its handheld systems. Conventional spectrometer designs with high optical throughput and large interrogation areas (large laser spot) require a large aperture in the spectrometer. This is counter to the requirement of high spectral resolution needed for spectral matching. This important spectral concept is called etendue and etendue controls a spectrometer’s sensitivity (light collection), resolution, and its interrogation area.
This Application Bulletin describes the advantages of using the optical focus technique – the Orbital-Raster-Scan (ORS) – in Metrohm’s handheld Raman system “Mira” over traditional techniques. Download your copy today to find out how this can benefit your identification needs.
