Raman Sensing
Raman Sensing - Related Videos
09:26
Raman Spectroscopy for Chemical Analysis
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2023
Source: Laboratory of Dr. Ryoichi Ishihara — Delft University of Technology Raman spectroscopy is a technique for analyzing vibrational and other low frequency modes in a system. In chemistry it is used to identify molecules by their Raman fingerprint. In solid-state physics it is used to characterize materials, and more specifically to investigate their crystal structure or crystallinity. Compared to other techniques for investigating the crystal structure (e.g. transmission electron...
04:17
Approximate Number Sense Test
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2023
Source: Laboratory of Jonathan Flombaum—Johns Hopkins University A common carnival game is to ask people to guess the number of jellybeans packed into a jar. The chances that anyone will get the exact number right are low. But what about the chances that someone will guess 17 or 147,000? Probably even less than the chances of guessing the correct answer; 17 and 147,000 just seem irrational. Why? After all, if the beans cannot be taken out and counted one-at-a-time, how can someone tell that an...
05:15
The Rouge Test: Searching for a Sense of Self
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2023
Source: Laboratories of Nicholaus Noles and Judith Danovitch—University of Louisville Humans are different from other animals in many ways, but one of the abilities that sets humans apart is their advanced ability to understand other people and simulate their thoughts and feelings, even when the thoughts and feelings do not align with their own. In scientific terms, these abilities are referred to as theory of mind, and this understanding is necessary for activities like giving compliments,...
07:44
Resonance Raman Spectroscopy of Extreme Nanowires and Other 1D Systems
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Cited by 1 •
2016
The paper describes a method for producing extreme nanowires by melt infiltration into carbon nanotubes and how 1D systems may be characterized and investigated using Resonance Raman Spectroscopy to determine vibrational and optical excitation energies.
06:48
A Multimodal Wide-Field Fourier-Transform Raman Microscope
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2025
A wide-field Fourier-transform microscope, based on a compact and ultra-stable birefringent interferometer, allows the parallel acquisition of spectra for all pixels of a 2D detector. The time-domain approach enables the disentanglement of photoluminescence and Raman signals, and allows rapid Raman mapping (~5 ms/pixel) with ~1-µm spatial and 23-cm-1 spectral resolution.
FAQs
The measured signal comes from inelastic scattering, in which a small fraction of the light scattered from an illuminated sample changes frequency. The amount of this shift corresponds to molecular vibrational behavior associated with the sample’s bonds. Because different materials produce different shifted features, the spectrum can function as a chemical fingerprint for identification and characterization.
The frequency shift carries information about molecular vibrations rather than simply the intensity of reflected or scattered illumination. This bond-related information gives Raman sensing chemical selectivity, allowing materials to be distinguished through their spectral features. That selectivity is particularly useful when engineering measurements must identify composition or detect material changes without relying on physical contact.
In engineering applications, Raman measurements can provide information about composition, stress, temperature, and changes in materials. These variables broaden the technique beyond simple identification: measurements can help track process conditions or assess the state of a structure. The relevant outcome depends on how the material’s Raman spectrum changes under the condition being examined.
A laser illuminates the sample while the measurement relies on the light scattered from that illuminated region, so the sensing approach does not require direct physical contact with the material. This supports chemical analysis and condition monitoring where touching the sample could interfere with a process, disturb a structure, or be impractical during operation.
A typical workflow begins by directing a laser onto the sample, collecting the scattered light, and examining the resulting spectrum for frequency-shifted features. Those features are interpreted as signatures of the material’s molecular vibrations. Since Raman sensing often requires little sample preparation, the workflow can support rapid measurements of engineering materials and processes.
Engineers may select this approach when they need rapid, selective information about material composition or changes during a process. Its noncontact character and limited sample-preparation requirements can support repeated measurements, while the chemical fingerprint helps evaluate whether materials meet expected conditions. These features make it relevant to quality control and process monitoring.
For structures and engineered materials, Raman measurements can be used to monitor stress, temperature, and material changes without requiring extensive preparation. The resulting spectral information can contribute to structural health assessment by indicating changes in the condition of the material. This makes the technique relevant when engineers need measurements that preserve the structure and support field-deployable instrumentation.