| 摘要 |
<p>In order to correct a specified aberration occurring in an optical system, a plurality of types of aberration correcting optical element (4) having a different correction amount and/or sign of aberration are provided. The amount and sign of aberration occurring in the optical system from a semiconductor laser (1) to an objective lens (6) except the aberration correcting optical element (4) are measure by means of an interferometer, or the like. Depending on the measured amount and sign of aberration, one type of aberration correcting optical element (4) is selected, as required, from among the plurality of types of aberration correcting optical element (4) such that the residual RMS wave aberration is minimized after correction and then it is inserted into the optical system from the semiconductor laser (1) to the objective lens (6).</p> |
