An explosives detector includes an infrared sampler having a flat infrared radiation source suitable for release of a solid explosive sample from a surface of a scanned subject using a wavelength of an infrared radiation, and a thermal decomposition unit having a silica glass tube with a silica glass tube gas inlet located in the flat infrared radiation source, wherein the silica glass tube is equipped with a heating element, the thermal decomposition unit being suitable for decomposing the solid explosive sample into a plurality of explosive molecular fragments. The explosives detector further includes a detector cartridge, having a cartridge body with a detection liquid inside, a molecular detection membrane fully submerged under a level of the detection liquid, and a sensing cap, where each explosive molecular fragment is detected by said detector cartridge and a single photon optical detection unit in communication with detector cartridge to provide a data stream indicative of explosive molecular fragment's presence in the solid explosive sample.