A combined / hybrid / hyphenated Raman system couples Raman analysis with another analytical technique – examples include Raman-AFM, Raman-PL and Raman- Epifluorescence. Hyphenated systems allow more complete sample analysis on a single bench top system, and offer lower cost of ownership compared with two individual systems. They also remove the need for time consuming alignment of a sample on separate systems to allow the same area to be analyzed with complementary techniques.
A range of combined Raman solutions exist, offering different capabilities to the user.
Combining Raman analysis with photoluminescence (PL) detection makes it possible to characterize both the vibrational and electronic properties of materials on a single bench top platform. Typical applications include analysis of semiconductor and nano-materials for band gap determination, impurity levels and defect detection, recombination mechanisms and material quality.
Combining Raman analysis with an Atomic Force Microscope (AFM) can provide topographic sample information on the nanometer scale, together with the chemical information obtained from Raman spectroscopy and imaging. The end result is a more comprehensive sample characterization. The combination of Raman and AFM also allows the investigation of Tip Enhanced Raman Scattering (TERS) for true nanoscale Raman analysis
Epifluorescence imaging is widely used within biological fields for visualization of cell/tissue materials, but does not offer the detailed molecular information that Raman can provide. Combining the two techniques on a single microscope system allows fast location of regions of interest within biological samples and targeted chemical analysis.
HORIBA Scientific partners with most of the world’s leading Scanning Electron Microscope (SEM) manufacturers to provide multi-characterization capabilities.
It is possible to combine Raman and photoluminescence (PL) on a single microscope system. Photoluminescence (PL) spectroscopy is a non-contact, non-destructive method of probing the electronic structure of materials. It is caused by a two-step photon absorption- emission process involving the electronic states of the material. The emission of light through this process is photoluminescence. By combining Raman analysis with PL detection, it is possible to characterize both the vibrational and electronic properties of materials on a single bench top platform.
Combined Raman-PL systems allow confocal mapping capabilities with sub-micron spatial resolution. A wide range of excitation wavelengths is possible, from the UV to NIR, allowing control of the penetration depth into the material, and thus, control of the volume sampled. Systems can be configured with different detectors such as CCDs and InGaAs, which provide high sensitivity detection from the UV out to 1.5 µm and beyond. Temperature stages can be used in combination with the Raman-PL systems allowing analysis of samples at temperatures down to 4.2K.
It is possible to combine Raman and epifluorescence on a single microscope system. Epifluorescence imaging is widely used within biological fields for visualization of cell/tissue materials, but does not offer the detailed molecular information that Raman can provide. Combining the two techniques on a single microscope system allows fast location of regions of interest within biological samples and targeted chemical analysis. Experiments such as FISH (fluorescence in situ hybridization) are routinely possible on such systems, allowing them to be combined with Raman chemical analysis.
Raman and AFM (Atomic Force Microscope) analysis can be combined on a single microscope system, opening interesting new capabilities and providing enhanced information on sample composition and structure by collecting physical and chemical information on the same sample area.
On one hand, AFM provide topographic, mechanical, thermal, electrical, and magnetic properties down to the molecular resolution (~ nm, over μm2 area), on the other hand confocal Raman spectroscopy and imaging provides specific chemical information about the material, with diffraction limited spatial resolution (sub-micron).
Techniques such as Tip Enhanced Raman Scattering (TERS) and Tip Enhanced Photoluminescence (TEPL) can also be undertaken with such systems, to open up the potential for true nanoscale spectroscopic analysis.
Two different configurations exist for the optical coupling of AFM/Raman systems: one in transmission and one in reflection.