Optical information storage utilizing the explosive crystallization of amorphous In1−xGaxSb films is reported. Information encoding is accomplished using a low power, focused laser beam to crystallize local areas of the film by normal nucleation and grain growth. The remainder of the film is ‘‘developed’’ by spontaneously propagating an explosive crystallization (EC) front. The formation can be retrieved by rastering a low intensity laser beam across the storage media and detecting the difference in optical reflectivity between the roughened EC matrix and the smooth highly reflecting laser annealed regions. A 15:1 signal‐to‐noise ratio has been obtained in initial experiments with 5 μm diameter recorded spots. The spot temperature and laser power densities required for writing with this approach are expected to be lower than in comparable techniques where melting or vaporization is required.