Raman Imaging Overview
Raman Microscopy Systems from WITec
When a laser interacts with a sample, the light scattered back is a spectrum of different energies due to vibration and/or rotation of the chemical bonds within the material. This Raman spectrum is unique for each composition, and can provide qualitative and quantitative information on the material under test. Raman spectroscopy provides a chemical fingerprint of the investigated compounds, is non-invasive, non-destructive, label-free and requires minimal, if any, sample preparation. It is also insensitive to water and can be used for imaging.
WITec combine an ultra-high throughput Raman spectroscopy technique with a superior quality optical imaging system to form a confocal microscope with unprecedented chemical sensitivity.
The properties of solids and liquids can be analysed with diffraction-limited spatial resolution (typically down to λ/2 of the excitation wavelength, ~200 nm) without labelling or any other sample preparation. The resulting Raman images deliver clear and detailed information related to the sample's chemical compounds and their distribution.
Ultra-fast Raman imaging
The key to ultra-fast Raman imaging is a system that is optimised in its entirety, be it the optical coupling, throughput efficiency, control electronics and high sensitivity sensor. The WITec Alpha and apyron provide this critical complete system optimisation.
Electron Multiplying CCD detector technology, that can acquire up to 1300 spectra per second, can further enhance the speed of acquisition of a complete Raman image.
Speed is advantageous when performing measurements on delicate samples that require the lowest possible levels of excitation power. The WITec sensitivity is unsurpassed in this aspect and so is an ideal system for the analysis of biological samples such as single cells or tissue imaging.
The confocality of the Raman microscope strongly reduces background signal from the sample. Generation of depth profiles and 3D images with exceptional spectral and spatial resolution becomes straightforward. WITec's fully confocal microscope systems are thus able to analyse the distribution of certain compounds throughout a sample with ease.
Correlative analysing techniques in one single instrument will always deliver a more comprehensive sample analysis. Fluorescence, luminescence, atomic force microscopy (AFM), near-field microscopy (SNOM or NSOM) and SEM are uniquely offered in conjunction with Raman by the WITec modular design. Combination of the various imaging techniques and switching between the different acquisition modes is simply done by rotating the microscope turret.
Raman and AFM
Raman and SNOM / TERS
TrueSurface - Realtime autofocus and sample tracking
TrueSurface is WITec's innovative answer to maintaining sample focus. Conducted simultaneously with the Raman analysis, the systems tracks the surface morphology seamlessly and with ultimate precision.
ParticleScout - Optically quantify and identify particulates
ParticleScout can survey, classify, analyse, quantify and identify particles using chemical characterisation over large sample areas. Its advanced categorisation tools facilitate the selection of relevant particles with unprecedented ease, and its user-defined classification by shape and size enables researchers to characterise many properties within the sample.
Boolean filters can be applied for precise grouping, and there is an automated mask creation feature for subsequent Raman analysis.
Categorisation can be carried out according to:
- Bounding box
- Max. or Min. Feret diameter
- Aspect ratio
- Equivalent diameter
- ...and many more
ParticleScout makes full use of Raman imaging's advantages in fast, label-free and nondestructive chemical characterisation while accelerating the workflow for the researcher. In seamless combination with WITec's TrueMatch database management software, the user can build a catalog of particles based on their constituent molecular components linked to physical attributes, such as size or aspect ratio, and produce a report that quantifies specific particles in a sample.
In addition to environmental science, ParticleScout is also of benefit to scientists working in pharmaceuticals, cosmetics, food technology, geosciences and manufacturing.
Brochures with more information about TrueMatch and ParticleScout can be downloaded from the Documents tab above.