Fig. 1. Schematic of the writing, reading, and erasing of optical information.

A focused 473 nm laser beam is irradiated into the glass, and the blue area is the photochromic region of the glass. The 3D optical data are written in transparent glass by a computer-controlled 3D XYZ translation stage. A 465 nm light from xenon lamp is used to excite the glass, and the photochromism-induced luminescence modification is recorded by a CCD camera. The transmittance or luminescence modulation is recovered by the thermal stimulation.