08 Dec 2015
Systems from Block Engineering and Alakai Defense employ Raman and other optical techniques to counter chemical weapon and bomb threats.
Two emerging US companies have developed optics-based detection systems that they say can provide protection for so-called “soft targets” that could be targeted by terrorists.
Massachusetts-based Block Engineering and Florida’s Alakai Defense Systems have adopted a variety of photonic components and phenomena, including quantum cascade lasers (QCLs), infrared spectroscopy and Raman scattering in their counter-terrorism products.
Block, which won a Prism Award back in 2011 for its “LaserScan” analyzer, says that two of its products are able to offer protection against chemical weapons. Its CEO Petros Kotidis said in a company announcement:
"Advances in laser technology and signal processing algorithms have enabled detection of dangerous chemicals, such as chemical warfare agents and toxic industrial gases, at very low concentrations."
Block’s “LaserWarn” system is, like its Prism-winning kit, based around mid-infrared QCLs. “Covering distances as long as 2-3 km, the system alarms in less than one second, when a dangerous chemical crosses the trip-wire beams anywhere in the protected area,” claims the firm. “The system provides the most sensitive, stand-off chemical detection available today and can operate indoors or outdoors on a continuous 24/7 mode with no consumables.”
Sarin and VX detection
According to the company’s spec sheet for LaserWarn, the optical system can detect the nerve agents sarin and VX at concentrations of just 26 parts per billion (over a 100 meter path length). It offers a standard range of 500 meters that can be extended to 3 km.
Block also sells a rapid-scan infrared spectrometer that is said to be capable of detecting chemical “clouds” at a distance of up to 5 km. The “Porthos” Fourier Transform Infrared (FTIR) system can be used either as a portable detector or installed at a fixed location on a tripod or a scanner for complete area coverage, and deployed either indoors or outdoors, says the firm.
Operating at wavelengths between 7.5 µm and 13.5 µm, Porthos is compact enough to have been deployed on UAVs (in an adapted form) and is said to detect the full range of nerve, blood and blister agents.
Both LaserWarn and Porthos feature internal chemical libraries of known chemical threats that can be expanded to include new threats and also to detect vapors from triacetone triperoxide (TATP), a common choice for those cooking up home-made explosives.
Deep-UV Raman advantages
Meanwhile Alakai Defense Systems’ explosives detector uses Raman scattering to provide stand-off detection at a distance of up to 50 meters. But unlike most Raman technology, it employs a deep-ultraviolet (DUV) laser source that the company says greatly speeds up the detection process.
Short-listed for a Prism Award at the SPIE Photonics West event taking place in San Francisco in February 2016, the “PRIED” system takes advantage of the greater scattering effect at shorter wavelengths to improve signal-to-noise performance.
PRIED is slated for release in early 2016, and its stand-off detection capability will, in Alakai’s view, drastically improve the safety of soldiers, first responders and others attempting to determine whether a suspect material is explosive.
Alakai is up against two miniature spectrometer technologies in the “detectors and sensors” Prism Award category, in the form of Hamamatsu Photonics’ MEMS Fabry-Perot interferometer and Spectral Engines’ similar “lab in your pocket” wireless infrared analyzer.
Headquartered in Largo and founded in 2009, Alakai says that its intellectual property includes methods to enhance the detection sensitivity of laser sensors, as well as proprietary algorithms for signal analysis, and novel optical designs.
The defense-focused firm has won various awards, and moved up the rankings of Inc. magazine’s “Inc 5000” list of fast-growing private companies to #2246 this year after posting revenue of $6.7 million in 2014.