Raman laboratory - samples

 Geological samples:
Laser Raman spectroscopy is used in our group primarily as a rapid tool for identification of minerals and characterization of microfossils in geological samples. We typically work with normal 30 um thinsections. For fluid inclusion studies 100 um thinsections are preferred. A typical analysis is entirely non-destructive, requires no further sample preparation, and takes place in a matter of seconds. Raman maps (i.e. chemical or mineralogical maps) and depth profiles can be constructed as well by obtaining thousands of spectra in a x,y- x,z- or y,z-grid. Such maps can be constructed in a matter of minutes to hours, depending on resolution (down to 0.3 um) and area (up to centimetres).
In geological and biological studies samples often need to be prepared for a range of dedicated in-situ techniques such as LA-ICP-MS, SIMS, NanoSIMS, SEM, TEM, EMP, and Synchrotron-based micro-analytical tools such as XRF and XANES. The rapid non-destructive character of Raman spectroscopy makes it the perfect tool for a first mineralogic characterization and recognition of areas of interest.

Some examples of Raman applications are:
- General mineral identification in rock slabs or thinsections
- Organic microfossils (2D- and potentially 3D-mapping)
- Opaque minerals (e.g. magnetite-series, sulfide-series)
- Carbonates (siderite-magnesite-dolomite-rhodocrosite-calcite)
- Carbonates in shells and microfossils (calcite-aragonite)
- Carbonaceous matter (graphite, kerogen, shungite)
- Mineral assemblages in hot spring sinters, hydrothermal vents
- High-pressure minerals at impact sites
- Mineral inclusions in e.g. diamonds
- Fluid-inclusions (semi-quantitative CO2-CH4-N2-H2O etc.)

Other samples:
Although emphasis in our group is on geological and biological samples, Raman spectroscopy can be applied to a wide variety of samples. The switching between different laser wavelengths (488, 514, 785 nm) allows optimization for certain types of materials. In addition, it allows in certain specific cases for Resonant Raman spectroscopy. Some interesting examples are:
- Dye in paintings
- Archaeological artefacts
- Material sciences: carbon nanotubes, silicon wafers
- Stress/strain studies: solar panels, diamonds
- Chemical processes: real time reaction analysis in micro-reactors
- Cryogenic samples: gas hydrates in ice