ABSTRACT
This chapter addresses the challenging task of detecting explosives and other materials from a safe distance. In essence, the challenge can be described in general terms as being able to detect and identify molecules that may be at very low concentration. While emphasis will be placed on explosives, it is understood the application fast detection of any other material such as toxins in a food production line. The greatest advantage of lasers for standoff detection is that the laser can be directed and focused on a target that is tens of meters away. The laser can be scanned over large areas, and if the laser is of sufficiently low power and at a wavelength that does not penetrate the eye, then it is safe to be used in public spaces without restrictions. It is important that the laser can detect a large variety of molecules; therefore, it makes sense to focus on the vibrational signature of molecules for identification.
