Open Access

The identification of energetic materials in containments is an important challenge for analytical methods in the field of safety and security. Opening a package without knowledge of its contents and the resulting hazards is highly involved with risks and should be avoided whenever possible. Therefore, preferable methods work non-destructive with minimal interaction and are capable of identifying target substances in a containment quickly and reliably. Most spectroscopic methods find their limits, if the target substance is shielded by a covering material. To solve this problem, a combined laser drilling method with subsequent identification of the target substance by means of Raman spectroscopic measurements through microscopic bore holes of the covering material is presented. A pulsed laser beam is used for both the drilling process and as an excitation source for Raman measurements in the same optical setup. Results show the ability of this new method to gain high-quality spectra even when performed through microscopic small bore channels. With the laser parameters chosen right, the method can even be performed on highly sensitive explosives like triacetone triperoxide (TATP). Another advantageous effect arises in an observed reduction in unwanted fluorescence signal in the spectral data, resulting from the confocal-like measurement setup with the bore hole acting as aperture.

Unattended luggage or containers in public areas, such as railway stations and buildings, like airports, may trigger bomb disposal operations. While these instances frequently involve harmless forgotten bags, they can also signal the presence of unconventional explosives and incendiary devices, which may include chemical, biological, radiological, nuclear, and explosive (CBRNe) elements. Research aspects of this work include the development of a mobile laser cutting system (LCS) to enhance the capabilities of police bomb disposal units in neutralizing improvised explosive devices (IEDs) and forensic evidence collection, thereby improving the safety of the public and defusing experts. This article presents the results of the development of a breakthrough detection system using an appropriate sensor technology. Parameters are determined by means of sensory monitoring to cut through various materials without interacting with the layer behind them. The investigation includes real cutting tests with the mobile LCS on various materials. For example, breakthrough times for polystyrene ranged from 75 to 250 s depending on geometry, while sensor accuracy in detecting cutting progress exceeded 90%. Additionally, explosive residues as low as 10 ng were successfully detected post-cutting, highlighting the system’s forensic compatibility. The results show that sensor-based breakthrough detection is feasible for the laser cutting of IED-relevant objects.