| 摘要 |
PROBLEM TO BE SOLVED: To attain a reproduction technique by which signal reproduction can be executed with an excellent SNR even when a reflectance difference between a formed part and a non-formed part of a recording mark is low.SOLUTION: For example, p-polarized light and s-polarized light are radiated on a recording layer of an optical recording medium so that respective radiation spots have a preceding-succeeding relationship, the p-polarized light and the s-polarized light having passed via the recording layer are overlapped, and the overlapped light is received via a polarizing plate. When, for example, one of the p-polarized light and s-polarized light is positioned on a mark, and the other is positioned at a non-formed part of the mark, an optical path difference (phase difference) is generated between the p-polarized light and the s-polarized light, so that a polarization direction of the overlapped light varies. On the other hand, when both of the p-polarized light and the s-polarized light are positioned on the formed part or the non-formed part of the mark, the polarization direction does not vary. Such variation in the polarization direction is detected as change in reception light amount by the polarizing plate so as to enable signal reproduction. |
