A thin film for recording data which is formed on a substrate directly or via a protection layer, and which develops change in the arrangement of atoms upon irradiation with a recording beam, wherein an average composition in the direction of film thickness is represented by the general formula, wherein X, Y, Z, .alpha. and .beta. are values that lie over the ranges of 0.ltoreq.X<30, 0.ltoreq.Y.ltoreq.40, 0.ltoreq.Z.ltoreq.70, 15.ltoreq.Y+Z.ltoreq.70, 10.ltoreq..alpha..ltoreq.65, 20.ltoreq..beta..ltoreq.70, E denotes at least one element between Se and S, D denotes at least one element among As, Sb, Si and Ge, C denotes at least one element among Bi, Sn and Pb, B denotes at least one element among Cu, Ag, Au, Sc, Y, Ti, Zr, V, Nb, Cr, Mo, Mn, Fe, Ru, Co, Rh, Ni and Pd, and A denotes an element or elements other than those elements denoted by E, D, C and B.

A recording medium comprises a substrate coated with a light reflecting layer which in turn is coated with a light absorbing layer selected from the group consisting of Pt complexes of bis-(dithio-.alpha.-diketones) which have the formula: ##STR1## wherein R is a phenyl or substituted phenyl group. During recording, portions of the absorbing layer are ablated, vaporized or melted by an intensity-modulated, focussed light beam, thereby exposing portions of the reflective layer and recording video information as a reflective-antireflective pattern.

An ablative recording medium comprises a substrate coated with a light reflecting layer which in turn is coated with a light absorptive layer of di-indeno[1,2,3-cd:1',2',3'-lm]perylene. During recording, portions of the light absorptive layer are ablated by a modulated focussed light beam, thereby exposing portions of the reflecting layer. Video information is recorded as a reflective-antireflective pattern.

A flat major surface of a disc-shaped substrate (e.g., of glass) is coated with a first light reflective layer (e.g., Rhodium) which is coated with a layer of a dielectric material (e.g., silicon dioxide) highly transparent of light of a frequency supplied by a playback laser, which transparent layer is coated with a second light reflective layer (e.g., Rhodium). The light output of a recording laser, which is intensity modulated in accordance with a signal to be recorded, is focused upon the coated surface of the disc as the disc is rotated. With the peak intensity of the focused light sufficient to at least cause melting of the second reflective layer, an information track is formed as a succession of spaced pits in which the first reflective layer is effectively exposed through the layer of dielectric material. For playback, light of a constant intensity is focused on the information track and the adjacent land areas as the disc is rotated. The focused light is of insufficient intensity to effect melting of the remaining portions of the second reflective layer, but is of a frequency at which the thickness of the dielectric layer exposed through the pits introduces a phase change of approximately (2K+1) .pi. radians between reflected portions of the focused light which fall on the pits and reflected portions of the focused light which fall on the undisturbed areas of the disc, where k is zero or any integer. A photodetector, positioned to receive light reflected from the information track as the pits pass through the path of the focused light, develops a signal representative of the recorded information.

An optical recording medium includes a substrate, a recording layer and a dielectric layer formed on said substrate, said dielectric layer containing a mixture containing at least a chalcogen compound and fluoride compound. The optical recording medium has excellent long term storage stability, excellent recording and erasing cycle characteristics and excellent recording and/or erasing characteristics.