This invention relates to a method and system for remote detection of a targeted substance by the appropriate application of a probing signal that induces molecular resonance in the target substance to create an identifiable signature or response. In the preferred embodiment, signals transmitted are an Infrared laser beam, amplitude modulated in the range of 100 kHz frequency. The probing signal stimulates molecular resonance of the target substance which produces characteristic electron signal responses that are detected by IR detectors. A software program is used to process the electrical response signals and to compare them with electrical response signals stored in a database of known substances, thus allowing the target substance to be identified. The system may also be used to locate targeted substances.