The Raman probe is the core component of a Raman spectrometer, mainly used to excite the sample with laser to generate Raman scattering, collect and analyze the frequency shift signal of the scattered light, and identify the molecular structure or chemical composition in the sample.
Based on the Raman scattering phenomenon, when a laser beam is irradiated onto a sample, a small portion of the light interacts with molecules in the sample, causing energy transfer and resulting in a decrease or increase in the energy of some photons, forming Raman scattering light. Raman spectroscopy contains vibrational information of sample molecules, and by analyzing Raman spectra, information such as the chemical composition, structure, and state of the sample can be obtained. Fiber optic is responsible for transmitting laser beams into the sample and collecting Raman optical signals back.
core functionality
Laser excitation: By focusing light onto the surface of the sample through a laser, molecular vibrations are induced and characteristic Raman scattering is generated.
Signal collection: Using a lens system to focus scattered light onto a detector (such as a fiber optic spectrometer) to achieve high-sensitivity detection.
Non destructive analysis: It can detect the chemical composition of living samples such as skin and biological tissues while maintaining sample integrity.
Raman probes are based on the Raman scattering effect: when a sample is irradiated with laser, molecular vibrations cause changes in photon energy, resulting in frequency shifted scattered light (Raman signal). The probe needs to complete three major functions:
Laser focusing and transmission: The laser is coupled into an optical fiber through a lens and focused onto the surface of the sample (such as solid, liquid, or gas).
Signal collection and filtering: Collect Raman signals from scattered light and filter out Rayleigh scattered light with an intensity 10 times higher through notch filters or holographic gratings to avoid signal flooding.
Fiber optic transmission and detection: The filtered signal is transmitted through fiber optic to the spectrometer, which converts it into an electrical signal and generates a Raman spectrum.