In war zones, at airport security screening, around oil refineries, in manufacturing facilities—the list of hazardous environments or potential danger reflects the nature of the modern world. Fortunately, threat detection techniques using optical sensing technologies are being developed to meet safety and security needs in these diverse situations. Our cover story, for example, is about a single-beam stimulated Raman scattering technique under development at Michigan State University that can detect and identify traces quantities of explosives at 1–10 m standoff distance on a variety of substrates (see page 15).
Techniques for threat detection also include Fourier transform infrared spectroscopy, Raman spectroscopy, and thermal imaging. Some require large or prohibitively expensive equipment, are susceptible to fluctuations in ambient conditions, have a weak signal, or involve laser sources that are not eye-safe. In this issue, researchers at M Squared Lasers describe a laser-based hyperspectral imaging technology that addresses these concerns. Initial development has been aimed at detecting and identifying deposits of chemical warfare agents on surfaces, but such a hyperspectral imaging system also could be used to identify substances of interest in oil and gas production, mining, food and drink processing, and forensics (see page 28).
Fingerprints are a valuable forensics tool for law enforcement, and for preventing identity theft and securing buildings. Researchers at Tel Aviv University contributed an article describing a portable low-coherence holography system for 3D fingerprint images, which should further broaden the number of potential applications (see page 54).
As this issue demonstrates, personal and societal security remains one of the greatest values supported by photonics.
