Raman spectroscopy is a molecular spectroscopic method based on the Raman effect. This is predicated on the inelastic scattering of electromagnetic radiation on molecules of a gaseous, liquid or solid material.
The energy shifts (Stokes and Anti-Stokes) in the scattered light are specific to the vibrations of the molecule`s chemical bonds, so that an individual spectral "fingerprint" for chemical compounds is obtained. This serves to characterize and identify the sample material. The interaction of the molecule with photons causes vibrations, whereby of 106 irradiated photons only approximately 1 photon is inelastically scattered. The low sensitivity can be counteracted in various ways, e.g. by resonant excitation (excitation wavelength in the electronic absorption of the sample) or higher laser power respectively excitation frequency (higher energy input).
In addition to the high molecular specificity, Raman spectroscopy is characterized by the possibility of analyses in an aqueous environment. This permits in situ analyses of low and macromolecular substances up to biological samples such as bacteria and cells.
Raman spectroscopy is a non-invasive imaging technique, so that neither staining nor fixing of the samples is necessary.
- Excitation laser (fiber coupled) with software operated laser power control
- 532 nm, 75 mW output power
- 785 nm, 125 mW output power
- Precise sample positioning (reproducibility ≥ 0.01 %)
- Excellent diffraction limited resolution (lateral 200 - 300 nm)
- Ultra-high throughput spectrometer
- UHTS300 for VIS (with gratings: 600 lines/mm and 1800 lines/mm)
- UHTS400 for NIR (inclusive gratings of 300 lines/mm and 1200 lines/mm)
- Detectors – highly sensitive, thermoelectrically cooled spectroscopic camera
- For VIS: backside thinned CCD chip, QE > 90 % in the range of 500 - 700 nm
- For NIR: backside thinned deep depletion CCD chip, QE > 95 % @ 800 nm
- Precise TrueScan controlled scanning stage
- Real-time large area topographic imaging (acquisition of the sample topography in real time during sample movement)
- Instant TrueSurface Raman microscopy (synchronously controlled Raman imaging using real-time topographic information)
- Confocal Raman spectral imaging (with high speed, sensitivity and resolution)
- Planar scans (x-y axes) as well as depth scans (z axis)
- Time series
- Acquisition of a Raman spectrum at each lateral and axial image pixel / single point
The Raman device is coupled with an atomic force microscope, so that topographic information is obtained in addition to chemical information. The sample does not need to be moved between the two measurements.
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WITec Wissenschaftliche Instrumente und Technologie GmbH
(combined with the atomic force microscope alpha300 A → alpha300 RA)