Defense News reports, there hasn't been a whole lot of progress made in figuring out how to stop these improvised explosive devices, or IEDs. There's no "single silver bullet out there that can stop this threat," a member of a Pentagon task force on IEDs told the journal. "As we find some solutions that may address a particular type of weapon they’re using, a particular tactic, they shift, find new ways to do things."

Every year, circa 2.5 million of landmines and IEDs are planted. This is a staggering number considering that removal of one landmine or IED costs about $1,000. The cost of manufacturing one IED or a landmine is in the vicinity of $5. Given the low cost and high mortality (it is estimated that ca. 80 people are killed by landmines every day), it is obvious that landmines and IEDs are a problem that is not going to go away anytime soon. Because these explosive devices are usually manufactured from plastics, they cannot be found by metal detectors; specially trained canine officers (dogs are trained to smell the out-gassing of the mine's explosive) and/or heavy equipment must be used to find and deactivate the devices. More information may be obtained here. Three examples are shown below:

Two on the left: Mine-detecting dogs are one of the most versatile and valuable tools available today to find landmines. Center: Heavy equipment such as the "Agri-flail" machine - a modified tractor with a flail consisting of a rotating drum with attached chain penetrates the surface by a few centimeters and absorbs the explosions of mines planted to that depth. Right: Lion II is a radar/metal detector mounted on a heavy truck. More information can be found in the catalog by Geneva International Centre for Humanitarian Demining.

A number of alternative methods for detection of landmines using their physical and/or chemical properties were developed and are currently tested by the Military. These include:
● Electromagnetic Wave Detection and Imaging Transceivers (Status: prototype is being evaluated);
● Combined Metal and Radar Detectors (Status: available to military);
● Electromagnetic (EM) sensor (Status: prototype is being evaluated);
● Ground Penetrating Radar (Status: prototype is being evaluated);
● Optical Trace Chemical Landmine Detection Systems (Status: available to military).

 Sadly, there is a significant downside of the mechanical demining by heavy machinery. Unfortunately, some of the landmines after the mechanical clearing remain in the ground unexploded, and are still explosive. For this reason, we consider manual demining more reliable. However, the manual demining has substantially higher cost ($/m²).

Left: OZM-72 Mine. Fuse broken off and showing signs of being struck by the demining machine. The mine, however, is still explosive. Right: PMN-2 mines collected after mechanical demining. All contain workable explosives and would not function as designed but could blind or blow off fingers if played with. Two of them detonated when sandbag was dropped on them.

 Ideally, we would have enough resources to find all the landmines and disable/remove them one by one to make absolutely sure that there are no live ones left deployed. Sadly, this does not seem to be possible, as the price/planting of the minefield and demining are so disparate (refer to above section "Murder by numbers"). Additionally, we need to be able to search for explosive charges in areas where heavy equipment or radars are not as useful, for example at the airports. There, subtle methods utilizing trace vapors from explosive charges are used. The presence of such vapors in the air may be detected by several methods including mass spectrometry or by optical methods. Because the the optical devices are generally more portable than clunky mass spectrometers, we became interested in developing materials for optical sensing of explosives.

In our previous research, we have developed substances that change the color of the light emitted by the material in the presence of TNT-based explosives at relatively low concentration (10 ppb). The material consists of a small portion of a proprietary chemical blended with commercially available polymer matrix. The response of the material is visualized as a blue light emitted under black-light illumination (the red light is an internal standard; changes in relative color intensity serve as a sensor signal):

These materials may be incorporated into a small device with a CCD camera to integrate the relative intensities of the light emitted by the material. The integrated output signal can be visualized as follows: The figure above shows pseudo-3D (X-Y-Intensity) graphs obtained by digitizing of the original images: the changes in relative color intensity serve as a sensor signal.