A Thermal Luminescent (TL) spectroscopy system and method for remote sensing and detection of surface chemical contamination involves irradiation of a target surface with energy from a near infrared pump beam, and measurement of TL liberated by that surface within a middle infrared (MIR) region. Fundamental molecular vibration modes of target contaminants present are briefly activated after the surface has been driven out of thermal equilibrium. An emissivity contrast between strata and target contaminant develops, peaks, and then subsides during a finite thermal window of detection opportunity in which detection of fingerprint identifiers for target contaminants is most probable. Target contaminant identification employs neural network models trained and tested against known molecular absorption frequencies of target contaminants. The use of a pump beam that radiates energy outside the MIR spectra of received TL reduces possible interference with the very weak MIR signals given off by target contaminants.