Analysis and experiments of readouts of photochromic disks

With disks modeled as transmittance-relief gratings and information character modeled as the convolution integral of round spots, diffraction theory of readouts of photochromic disks is achieved based on Fourier transforms. Utilizing the Matlab programs, the readout curves of the RLL modulated disks are simulated. In the actual experiments of photochromic storage, with low or medium writing power, the readout signals accord well with the Matlab-calculated curves, while they differ a little when the writing power is higher.