Spatially Offset Raman Spectroscopy ProbeSORS
Non-Invasive Through-Container Chemical Detection for Security Screening and Defence Applications
The SORS Spatially Offset Raman Spectroscopy Probe is a precision spectroscopic probe designed and supplied by System Controls for non-invasive chemical characterisation through opaque and non-metallic containers. Unlike conventional Raman spectroscopy, SORS collects the signal from a point spatially offset from the illuminated area, enabling detection of concealed substances through coloured glass, HDPE bottles and teflon layers without opening or damaging the container. Available in 532nm and 785nm probe configurations with motorised, software-controlled offset adjustment from 0.5mm to 20mm ring radius, it is suited for security screening at airports, railway stations, defence perimeters and critical infrastructure sites.
What is SORS?
Spatially Offset Raman Spectroscopy (SORS) is a spectroscopic technique that allows non-invasive chemical characterisation of diffusely scattering materials ranging from opaque plastics to biological tissues. Conventional Raman spectroscopy can only analyse surface materials and cannot detect substances inside opaque containers. In real security screening scenarios, materials must be identified through coloured glass, HDPE, teflon and tetra packing without opening the container. The SORS technique collects the Raman signal from a point spatially separated from the illuminated area, overcoming the limitations of conventional Raman and enabling through-container detection. The System Controls SORS probe provides motorised, software-controlled offset adjustment across a ring radius of 0.5mm to 20mm in 0.5mm steps and is available in 532nm and 785nm probe configurations for different application requirements.
| Parameter | Specification |
|---|---|
| Probe at 532 nm laser wavelength | |
| Transmitting wavelength | 532 nm |
| Receiving wavelength range | 530–635 nm |
| Optical layout | Co-axial/bi-axial |
| Diameter of receiving optics | 25 mm |
| Focusing/collection spot | ~100 μm |
| Offset form | Laser beam in ring form and ring should be co-centric with collection spot |
| Offset range | Ring radius should be variable from 0.5 mm to 20 mm with step of 0.5 mm at a distance of 25 mm approximately |
| Length of both coupling fibers (transmitting and receiving ends) | ≤ 1 m |
| Probe at 785 nm laser wavelength | |
| Transmitting wavelength | 785 nm |
| Receiving wavelength range | 780–1050 nm |
| Optical layout | Co-axial/bi-axial |
| Diameter of receiving optics | 25 mm |
| Focusing/collection spot | ~100 μm |
| Offset form | Laser beam in ring form and ring should be co-centric with collection spot |
| Offset range | Ring radius should be variable from 0.5 mm to 20 mm with step of 0.5 mm at a distance of 25 mm approximately |
| Length of both coupling fibers (transmitting and receiving ends) | ≤ 1 m |
Through-Container Detection Without Opening the Package
SORS collects the Raman signal from a point spatially separated from the laser illumination point, enabling chemical characterisation through coloured glass bottles, HDPE bottles and teflon layers without opening, puncturing or damaging the container. This non-destructive, non-contact capability is the fundamental advantage of SORS over conventional Raman spectroscopy and the primary reason for its adoption in security screening applications at airports, railway stations and defence perimeter access control points.
Compact Fiber-Coupled Probe Architecture
The probe delivers the SORS measurement through fiber coupling with SMA type receiving connectors and transmitting fiber connectors compatible with standard fiber-coupled lasers. Coupling fiber length of 1 metre or less on both ends enables flexible integration with external spectrometer and laser hardware. The co-axial or bi-axial optical layout is determined at the optical design stage to optimise collection efficiency and offset range for the specific application.
Motorised Software-Controlled Offset Adjustment
he offset ring radius is motorised and adjustable from 0.5mm to 20mm in 0.5mm steps via software control at approximately 25mm working distance. This programmable offset adjustment allows the operator to optimise the collection geometry for different container types and thicknesses, maximising the signal collected from within the container relative to the surface signal, which is the fundamental mechanism that enables through-container detection.
Broad Application Range Across Security and Science
SORS applications span airport and railway station baggage screening, defence perimeter and access control screening, forensic material analysis, pharmaceutical product verification, disease diagnosis research, energy technology material analysis and analysis of objects of art. The same probe hardware serves all these applications, with the detection specificity of Raman spectroscopy providing material identification rather than simply the presence or absence of a target substance.
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Non-invasive chemical characterisation through opaque containers for security screening at airports, railway stations and defence perimeters, as well as forensics, pharmaceuticals, life sciences and energy technology.
Conventional Raman cannot detect through opaque containers. SORS collects signal from a spatially offset point, enabling through-container detection through coloured glass, HDPE and teflon without opening the container.
Coloured glass bottles, HDPE bottles and teflon layers, covering the container types encountered in airport, railway and critical infrastructure screening.
532nm (530-635nm receiving) and 785nm (780-1050nm receiving). Both use 25mm receiving optics, ~100 µm collection spot and SMA receiving connectors.
0.5mm to 20mm ring radius in 0.5mm steps, motorised and software-controlled at approximately 25mm working distance.
532nm for visible wavelength excitation. 785nm for samples with high fluorescence interference. Contact System Controls sales team for application-specific guidance.
SMA type for receiving fiber. Transmitting fiber compatible with fiber-coupled laser connectors. Coupling fiber 1m or less on both ends.
Security screening (airports, railway stations, defence perimeters), forensics, pharmaceuticals, life sciences, energy technology and carbon material analysis.
