Abstract: A method for patterning a recording medium selectively thermally couples a recording medium and a heat source to alter a chemical composition of the recording medium. An apparatus for patterning a recording medium has a heat source for generating and directing an incident thermal wave to a recording medium so as to alter a chemical composition of the recording medium, and a controller for coordinating a mutual position of the incident thermal wave and the recording medium for inducing a direct thermal coupling between the recording medium and the heat source.