Surface-Enhanced Raman Scattering for Explosive Detection

Surface-Enhanced Raman Scattering (SERS) exploits the amplification of Raman signals by plasmonic nanostructures to identify trace amounts of explosive compounds with high specificity and sensitivity. By coupling incident laser light to the collective oscillations of conduction electrons in metallic nanostructures—typically silver or gold—the electromagnetic field at the surface is locally intensified, creating “hot spots” where Raman scattering from adsorbed molecules is dramatically enhanced. This technique overcomes the inherently weak cross-section of conventional Raman spectroscopy, enabling detection limits down to picomolar or even femtomolar levels. Such performance is crucial for security screening, environmental monitoring and humanitarian demining, where the low vapour pressures and complex matrices of nitroaromatic and nitroamine explosives challenge alternative methods. Advances in substrate design—ranging from nanoparticle-decorated porous silicon to laser-fabricated alloy nanoparticles and long-range periodic gratings—have improved reproducibility, portability and field readiness. Integration with handheld Raman instruments now supports rapid, in-situ detection, while ongoing research focuses on enhancing robustness, multiplexing capability and quantification in ambient conditions.

Research from Nature Portfolio

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Research from all publishers

Recent studies have demonstrated the efficacy of plasmonic nanogap substrates for solution-phase detection of nitro-based explosives. Tailored gaps between metallic features concentrate the electromagnetic field, producing distinct SERS fingerprints of TNT, RDX and PETN at picomolar concentrations under low laser power. Complementary work has employed free-standing porous silicon coated with silver nanoparticles to achieve robust, low-cost substrates. These platforms combine high density of hot spots with mechanical flexibility, attaining detection limits in the nanomolar range for common explosives and pesticides while maintaining stability over months. More recently, ultrafast laser techniques using a picosecond Bessel beam have fabricated gold-coated silver nanostructures with sub-200 nm features. These hierarchically structured substrates exhibit enhancement factors approaching 10^8 and enable trace-level identification of multiple hazardous molecules—including picric acid and ammonium nitrate—with sustained performance in real-time ageing studies. Together, these advances underscore a trend towards highly reproducible, field-deployable SERS sensors that balance sensitivity with operational simplicity.

Surface-Enhanced Raman Scattering for Explosive Detection publication trend

The graph below shows the total number of articles in surface-enhanced raman scattering for explosive detection across all publications each year (not limited to Nature Index journals).

Technical terms

Surface-Enhanced Raman Scattering (SERS): A spectroscopic technique in which the Raman signal from molecules is greatly amplified by proximity to plasmonic nanostructures.

Plasmonic Nanostructure: A metallic nanoparticle or patterned surface that supports collective oscillations of conduction electrons, enhancing local electromagnetic fields.

Hot Spot: A highly localised region of intensified electromagnetic field on a plasmonic substrate, responsible for maximal SERS enhancement.

Enhancement Factor (EF): A measure of the increase in Raman signal intensity afforded by a SERS substrate relative to conventional Raman scattering.

Limit of Detection (LOD): The lowest concentration of an analyte that produces a distinguishable SERS signal above the background noise.

References

1. Femtosecond Laser Fabricated Ag@Au and Cu@Au Alloy Nanoparticles for Surface Enhanced Raman Spectroscopy Based Trace Explosives Detection. Frontiers in Physics (2018).
2. Composite Sinusoidal Nanograting With Long-Range SERS Effect for Label-Free TNT Detection. Photonic Sensors (2018).
3. Detection of Explosives by SERS Platform Using Metal Nanogap Substrates. Sensors (2021).
4. Trace level detection of explosives and pesticides using robust, low-cost, free-standing silver nanoparticles decorated porous silicon.. Optics Express (2021).
5. Picosecond Bessel Beam Fabricated Pure, Gold-Coated Silver Nanostructures for Trace-Level Sensing of Multiple Explosives and Hazardous Molecules. Materials (2022).