Three-dimensional optical data storage in a novel photochromic material with two-photon writing and one-photon readout

We have demonstrated three-dimensional optical data storage in a novel photochromic material with two-photon excitation. The data are read out with a homemade confocal fluorescence microscope combined with the three-dimensional writing system. Since the degree of destruction is closely related with the total dwell time of the readout laser, we try to read out the data through an optimization among the doped concentration of photochromic material of the PMMA film, the readout power, and the dwell time of the laser at each data bit. Using the optimized readout condition, it is possible to achieve 107 readout cycles with very little erasure of the data at the scanning speed of a 50× CD driver. © 2005 Society of Photo-Optical Instrumentation Engineers.