An ultra-high-density data storage device that relies on optical signals. The device includes a luminescent layer that emits light when stimulated by an electron beam. The device also includes a phase-change layer that contains data bits that may absorb or reflect the stimulated light before the light reaches a detector. Also, a method of data storage and retrieval that includes writing data bits in the phase-change layer, stimulating emissions in the luminescent layer, and reading data bits by monitoring the amount of light that reaches the detector.