ACCESSING 3D MEMORY INFORMATION BY MEANS OF NONLINEAR ABSORPTION

A novel method for accessing information from two-photon 3D volume mem ory devices is presented. We have used the decrease in laser intensity induced by two-photon absorption as the means for reading 3D informat ion. The ratio of the initial laser intensity to the intensity after t wo-photon absorption is increased drastically by passing both beams th rough a second and fourth harmonic crystal. This means eliminates the need for focusing and collecting lenses and the disadvantages associat ed with the fluorescence method of reading information.