An optical recording medium, an optical recording system and an optical recording method, based on the suppression of the absorption coefficient of a polymer film (11) at selective wavelength in the infra-red as a result of irradiating the film (11) with a beam of a CO2 laser (13). The magnitude of the effect, which is observable only above a threshold power of the laser beam, is related to the energy deposited by the writing beam. Optical recorded information is stored in the modified absorbance spectrum of the polymer (11) and is read by an infra-red photometric device in the transmission mode.
