| 摘要 |
A multilayer optical recording medium including a first recording layer for recording or reproducing information by using a first light beam having a center wavelength lambda1, a first photochromic layer provided on the first recording layer, and a first optical waveguide layer provided on the first photochromic layer for guiding to the first photochromic layer a second light beam having a center wavelength lambda2 different from the center wavelength lambda1. The multilayer optical recording medium further includes a second recording layer provided on the first optical waveguide layer for recording or reproducing information by using the first light beam, a second photochromic layer provided on the second recording layer, and a second optical waveguide layer provided on the second photochromic layer for guiding the second light beam to the second photochromic layer. The first and second photochromic layers become transparent to the first light beam by irradiation with light or by application of heat. The reflectance of each of the first and second photochromic layers to the first light beam can be repeatedly increased by irradiation with the second light beam and can be repeatedly decrease to restore the transparent state.
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