In a multilayer recordable optical medium, each recording layer includes a
luminophore that fluoresces under reading laser light and a quencher
capable of quenching the luminophore fluorescence. Initially, the
luminophore and the quencher are not intermixed, so that the default state
of the luminophore is fluorescent. During writing, focused writing
radiation heats a spot in the medium so as to cause the luminophore and
the quencher to be intermixed, thereby quenching the fluorescence.