Frequently Asked Questions
Raman spectrometer is an analytical instrument that conducts vibrational spectroscopy on a sample. It can provide detailed information on the chemical composition of various compounds.
Raman spectroscopy finds applications in identifying various molecular components, given the vibrational frequency of the molecular bonds is within the accessible spectral range for typical Raman spectrometers. They are often used to characterize and identify artwork, and important historical documents. They can also be used in food and drug manufacturing industries to characterize products and identify or test for harmful pathogens.
Raman spectroscopy relies on inelastic scattering of monochromatic light of a laser source. As the incident light scatters from a sample, the wavelength of the scattered photons changes due to the interaction of the light with matter. This frequency (wavelength) shift, often referred to as a Raman shift, can become an important marker for the chemical compound being investigated. This is because the molecular bonds are often characterized with distinct and often well documented vibrational frequencies. By comparing the collected spectrum with the library of frequencies that map to specific chemical compounds, Raman spectrometer can uniquely identify the molecular compounds under investigation.
While the underlying principle remains the same, Raman spectroscopy is often classified into the following main sub-types: Resonance Raman Spectroscopy, Surface-enhanced Raman Spectroscopy, Micro-Raman Spectroscopy, and Non-linear Raman Spectroscopic Techniques.
While both Raman and FTIR spectroscopy rely on frequency resolved signal from the sample, Raman spectroscopy relies on measuring the energy of inelastically scattered photons and calculates the difference in energy between exciting and scattered photons. In contrast, FTIR (Fourier-Transform Infrared) spectroscopy measures the infrared spectrum of absorption or emission in a sample.
Raman spectroscopy is a non-invasive technique that can quickly identify various chemical compounds based on existing rich library of vibrational frequencies readily available for many common compounds. Advances in optical technologies have recently allowed significant miniaturization of this technology to the point where hand-held Raman spectrometers have become commercially available.
Raman microscope is an analytical tool that combines an optical microscope and a Raman spectrometer to conduct spatially resolved Raman spectroscopy. It allows creating a detail map of Raman signals coming from different spatial points within the field of view of the microscope.
Did You know?
1 - Intro to Raman Spectroscopy
2 - What is Raman Spectroscopy?
3 - Wikipedia