deposited on a polycarbonate substrate this layer is then covered with a layer of tellurium te also with a thickness of 40 nm the irradiation of the overall stack of the two layers forming the light sensitive film by means of a cw laser beam induces synthesis of the cdte compound which absorbs light below 620 nm the optical contrast c between the non irradiated areas of the film and those areas which have been irradiated is equal to 0 33 demonstrating the importance of the choice of the selected elements in forming the sensitive layer maintained at ambient for a period of 25 years the film retains an unchanged contrast c at 0 33 a layer of tellurium te is deposited on a polycarbonate substrate and this layer of te is then covered by a layer of al the two layers have the same thickness of 20 nm and their stack forms a film sensitive to light the laser irradiation of the thus formed film is carried out for 10 u2212 6 s with the beam emitted by a laser diode emitting in the near infrared 690 nm with a power of 10 mw after irradiation the irradiated area is completely black with an optical contrast c equal to 0 80 a layer of tellurium te of 20.